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1. A Repeating Fast Radio Burst Source in a Low-luminosity Dwarf Galaxy

Author

Danté M. Hewitt, Mohit Bhardwaj, Alexa C. Gordon, Aida Kirichenko, Kenzie Nimmo, Shivani Bhandari, Ismaël Cognard, Wen-fai Fong, Armando Gil de Paz, Akshatha Gopinath, Jason W. T. Hessels, Franz Kirsten, Benito Marcote, Vladislavs Bezrukovs, Richard Blaauw, Justin D. Bray, Salvatore Buttaccio, Tomas Cassanelli, Pragya Chawla, Alessandro Corongiu, William Deng, Hannah N. Didehbani, Yuxin Dong, Marcin P. Gawroński, Marcello Giroletti, Lucas Guillemot, Jeff Huang, Dmitriy V. Ivanov, Ronniy C. Joseph, Victoria M. Kaspi, Mikhail A. Kharinov, Mattias Lazda, Michael Lindqvist, Giuseppe Maccaferri, Lluis Mas-Ribas, Kiyoshi W. Masui, Ryan Mckinven, Alexey Melnikov, Daniele Michilli, Andrey G. Mikhailov, Anya E. Nugent, Omar S. Ould-Boukattine, Zsolt Paragi, Aaron B. Pearlman, Ue-Li Pen, Ziggy Pleunis, Ketan R. Sand, Vishwangi Shah, Kaitlyn Shin, Mark P. Snelders, Tiziana Venturi, Na Wang, David R. A. Williams-Baldwin, Jun Yang, and Jianping P. Yuan

Subjects
Radio bursts, Radio transient sources, Very long baseline interferometry, Dwarf galaxies, Astrophysics, QB460-466
Abstract

We present the localization and host galaxy of FRB 20190208A, a repeating source of fast radio bursts (FRBs) discovered using CHIME/FRB. As part of the Pinpointing REpeating ChIme Sources with EVN dishes repeater localization program on the European VLBI Network (EVN), we monitored FRB 20190208A for 65.6 hr at ∼1.4 GHz and detected a single burst, which led to its very long baseline interferometry localization with 260 mas uncertainty (2 σ ). Follow-up optical observations with the MMT Observatory ( i ≳ 25.7 mag (AB)) found no visible host at the FRB position. Subsequent deeper observations with the Gran Telescopio Canarias, however, revealed an extremely faint galaxy ( r = 27.32 ± 0.16 mag), very likely (99.95%) associated with FRB 20190208A. Given the dispersion measure of the FRB (∼580 pc cm ^−3 ), even the most conservative redshift estimate ( ${z}_{\max }\sim 0.83$ ) implies that this is the lowest-luminosity FRB host to date (≲10 ^8 L _⊙ ), even less luminous than the dwarf host of FRB 20121102A. We investigate how localization precision and the depth of optical imaging affect host association and discuss the implications of such a low-luminosity dwarf galaxy. Unlike the other repeaters with low-luminosity hosts, FRB 20190208A has a modest Faraday rotation measure of a few tens of rad m ^−2 , and EVN plus Very Large Array observations reveal no associated compact persistent radio source. We also monitored FRB 20190208A for 40.4 hr over 2 yr as part of the Extragalactic Coherent Light from Astrophysical Transients repeating FRB monitoring campaign on the Nançay Radio Telescope and detected one burst. Our results demonstrate that, in some cases, the robust association of an FRB with a host galaxy will require both high localization precision and deep optical follow-up.

Published
2024
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2. Mapping Obscured Star Formation in the Host Galaxy of FRB 20201124A

Author

Yuxin Dong, Tarraneh Eftekhari, Wen-fai Fong, Adam T. Deller, Alexandra G. Mannings, Sunil Simha, Navin Sridhar, Marc Rafelski, Alexa C. Gordon, Shivani Bhandari, Cherie K. Day, Kasper E. Heintz, Jason W. T. Hessels, Joel Leja, Clancy W. James, Charles D. Kilpatrick, Elizabeth K. Mahony, Benito Marcote, Ben Margalit, Kenzie Nimmo, J. Xavier Prochaska, Alicia Rouco Escorial, Stuart D. Ryder, Genevieve Schroeder, Ryan M. Shannon, and Nicolas Tejos

Subjects
Magnetars, Star formation, Radio transient sources, Astrophysics, QB460-466
Abstract

We present high-resolution 1.5–6 GHz Karl G. Jansky Very Large Array and Hubble Space Telescope (HST) optical and infrared observations of the extremely active repeating fast radio burst (FRB) FRB 20201124A and its barred spiral host galaxy. We constrain the location and morphology of star formation in the host and search for a persistent radio source (PRS) coincident with FRB 20201124A. We resolve the morphology of the radio emission across all frequency bands and measure a star formation rate (SFR) ≈ 8.9 M _⊙ yr ^−1 , approximately ≈2.5–6 times larger than optically inferred SFRs, demonstrating dust-obscured star formation throughout the host. Compared to a sample of all known FRB hosts with radio emission, the host of FRB 20201124A has the most significantly obscured star formation. While HST observations show the FRB to be offset from the bar or spiral arms, the radio emission extends to the FRB location. We propose that the FRB progenitor could have formed in situ (e.g., a magnetar born from a massive star explosion). It is still plausible, although less likely, that the progenitor of FRB 20201124A migrated from the central bar of the host. We further place a limit on the luminosity of a putative PRS at the FRB position of L _6.0GHz ≲ 1.8 ×10 ^27 erg s ^−1 Hz ^−1 , among the deepest PRS luminosity limits to date. However, this limit is still broadly consistent with both magnetar nebulae and hypernebulae models assuming a constant energy injection rate of the magnetar and an age of ≳10 ^5 yr in each model, respectively.

Published
2024
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3. Constraints on the Persistent Radio Source Associated with FRB 20190520B Using the European VLBI Network

Author

Shivani Bhandari, Benito Marcote, Navin Sridhar, Tarraneh Eftekhari, Jason W. T. Hessels, Danté M. Hewitt, Franz Kirsten, Omar S. Ould-Boukattine, Zsolt Paragi, and Mark P. Snelders

Subjects
Radio transient sources, Very long baseline interferometry, Astrometry, Radio continuum emission, Dwarf galaxies, Astrophysics, QB460-466
Abstract

We present very long baseline interferometry (VLBI) observations of a continuum radio source potentially associated with the fast radio burst source FRB 20190520B. Using the European VLBI network, we find the source to be compact on VLBI scales with an angular size of

Published
2023
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5. CASA on the fringe -- Development of VLBI processing capabilities for CASA

Author

Ilse M. van Bemmel, Mark Kettenis, Des Small, Michael Janssen, George A. Moellenbrock, Dirk Petry, Ciriaco Goddi, Justin D. Linford, Kazi L. J. Rygl, Elisabetta Liuzzo, Benito Marcote, Olga S. Bayandina, Neal Schweighart, Marjolein Verkouter, Aard Keimpema, Arpad Szomoru, and Huib Jan van Langevelde

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astronomy software, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Radio astronomy, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Very long baseline interferometry
Abstract

New functionality to process Very Long Baseline Interferometry (VLBI) data has been implemented in the CASA package. This includes two new tasks to handle fringe fitting and VLBI-specific amplitude calibration steps. Existing tasks have been adjusted to handle VLBI visibility data and calibration meta-data properly. With these updates, it is now possible to process VLBI continuum and spectral line observations in CASA. This article describes the development and implementation, and presents an outline for the workflow when calibrating European VLBI Network or Very Long Baseline Array data in CASA. Though the CASA VLBI functionality has already been vetted extensively as part of the Event Horizon Telescope data processing, in this paper we compare results for the same dataset processed in CASA and AIPS. We find identical results for the two packages and conclude that CASA in some cases performs better, though it cannot match AIPS for single-core processing time. The new functionality in CASA allows for easy development of pipelines or Jupyter notebooks, and thus contributes to raising VLBI data processing to present day standards for accessibility, reproducibility, and reusability., PASP in press, joint submission with the CASA reference paper; 12 pages, 5 figures

Published
2022

6. Highly polarized microstructure from the repeating FRB 20180916B

Author

A. Keimpema, K. Nimmo, F. Kirsten, Z. Paragi, Benito Marcote, Anne M. Archibald, Ramesh Karuppusamy, Jason W. T. Hessels, D. Z. Li, James M. Cordes, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Linear polarization, Scattering, Fast radio burst, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics, Polarization (waves), Position angle, 01 natural sciences, Orders of magnitude (time), 0103 physical sciences, Very-long-baseline interferometry, 010303 astronomy & astrophysics, Circular polarization, 0105 earth and related environmental sciences
Abstract

Fast radio bursts (FRBs) are bright, coherent, short-duration radio transients of as-yet unknown extragalactic origin. FRBs exhibit a variety of spectral, temporal and polarimetric properties that can unveil clues into their emission physics and propagation effects in the local medium. Here, we present the high-time-resolution (down to 1 μs) polarimetric properties of four 1.7 GHz bursts from the repeating FRB 20180916B, which were detected in voltage data during observations with the European Very Long Baseline Interferometry Network. We observe a range of emission timescales that spans three orders of magnitude, with the shortest component width reaching 3–4 μs (below which we are limited by scattering). We demonstrate that all four bursts are highly linearly polarized (≳80%), show no evidence of significant circular polarization (≲15%), and exhibit a constant polarization position angle (PPA) during and between bursts. On short timescales (≲100 μs), however, there appear to be subtle PPA variations (of a few degrees) across the burst profiles. These observational results are most naturally explained in an FRB model in which the emission is magnetospheric in origin, in contrast to models in which the emission originates at larger distances in a relativistic shock. High-time-resolution observations of the repeating fast radio burst source FRB 20180916B reveal changes to the polarization properties of the emission on timescales of a few microseconds, indicating an origin in the source magnetosphere.

Published
2021

7. AU-scale radio imaging of the wind collision region in the brightest and most luminous non-thermal colliding wind binary Apep

Author

Jamie Stevens, Robert Schulz, Philip G. Edwards, Joseph R. Callingham, Y. Han, Benito Marcote, M. De Becker, and Peter G. Tuthill

Subjects
Radiation mechanisms: non-thermal, Radio continuum: stars, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Binary number, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - high energy astrophysical phenomena, 01 natural sciences, Astrophysics - solar and stellar astrophysics, Binaries: close, 0103 physical sciences, Thermal, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Colliding-wind binary, Nebula, 010308 nuclear & particles physics, Astronomy and Astrophysics, Stars: individual: Apep, Plume, Stars, Space and Planetary Science, Techniques: interferometric, Spiral (railway), Order of magnitude
Abstract

The recently discovered colliding-wind binary (CWB) Apep has been shown to emit luminously from radio to X-rays, with the emission driven by a binary composed of two Wolf-Rayet (WR) stars of one carbon-sequence (WC8) and one nitrogen-sequence (WN4-6b). Mid-infrared imaging revealed a giant spiral dust plume that is reminiscent of a pinwheel nebula but with additional features that suggest Apep is a unique system. We have conducted observations with the Australian Long Baseline Array to resolve Apep's radio emission on milliarcsecond scales, allowing us to relate the geometry of the wind-collision region to that of the spiral plume. The observed radio emission shows a bow-shaped structure, confirming its origin as a wind-collision region. The shape and orientation of this region is consistent with being originated by the two stars and with being likely dominated by the stronger wind of the WN4-6b star. This shape allowed us to provide a rough estimation of the opening angle of $\sim 150^\circ$ assuming ideal conditions. The orientation and opening angle of the emission also confirms it as the basis for the spiral dust plume. We also provide estimations for the two stars in the system to milliarcsecond precision. The observed radio emission, one order of magnitude brighter and more luminous than any other known non-thermal radio-emitting CWB, confirms it is produced by an extremely powerful wind collision. Such a powerful wind-collision region is consistent with Apep being a binary composed of two WR stars, so far the first unambiguously confirmed system of its kind., Comment: 9 pages, 3 figures, accepted for publication in MNRAS

Published
2020
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8. Radio modelling of the brightest and most luminous non-thermal colliding-wind binary Apep

Author

S. Bloot, Joseph R. Callingham, and Benito Marcote

Subjects
Physics, Colliding-wind binary, High Energy Astrophysical Phenomena (astro-ph.HE), Infrared, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Stars - individual - Apep, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Thermal, Astrophysics::Solar and Stellar Astrophysics, Exponential decay, Anisotropy, Absorption (electromagnetic radiation), Astrophysics - High Energy Astrophysical Phenomena, Stars - Wolf-Rayet, Order of magnitude, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract

Apep is the brightest and most luminous non-thermal colliding-wind binary by over an order of magnitude. It has been suggested from infrared observations that one of the Wolf-Rayet stars in Apep is launching an anisotropic wind. Here we present radio observations of Apep from 0.2 to 20 GHz taken over 33 years. The spectrum reveals an extremely steep turnover in the flux density at low frequencies, where the flux density decreases by two orders of magnitude over only 325 MHz of bandwidth. This exponential decline is best described by free-free absorption, with a turnover frequency at 0.54 $\pm$ 0.01 GHz. Above the turnover, the spectrum is well described by a power-law and a high-frequency cut-off likely caused by inverse-Compton cooling. The lightcurve of Apep shows significant variation over the observing period, with Apep brightening by over 50 mJy in a span of 25 years at 1.4 GHz. Models that assume spherical winds do not replicate all of the structure evident in the radio lightcurve. We derived a model that allows one of the winds in the system to be anisotropic. This anisotropic model recovers most of the structure of the lightcurve and is a significantly better statistical fit to the data than the spherical wind model. We suggest such a result is independent support that one of the Wolf-Rayet stars in Apep is launching an anisotropic wind. If the anisotropic wind model is correct, we predict a ~25% decrease of the 1.4 GHz flux density of Apep over the next five years., 14 pages, 6 figures, accepted for publication in MNRAS

Published
2021

9. LOFAR Detection of 110-188 MHz Emission and Frequency-dependent Activity from FRB 20180916B

Author

V. M. Kaspi, Cherry Ng, A. Naidu, P. J. Boyle, Cees Bassa, K. Nimmo, B. W. Meyers, Ramesh Karuppusamy, Yashwant Gupta, Kyung-Hoon Shin, D. Z. Li, Mohit Bhardwaj, Kiyoshi Masui, D. Michilli, Emmanuel Fonseca, Ingrid H. Stairs, Jason W. T. Hessels, F. Kirsten, B. C. Andersen, Mubdi Rahman, P. Chawla, V. I. Kondratiev, Zsolt Paragi, A. Josephy, C. Brar, T. Cassanelli, Ziggy Pleunis, R. Mckinven, Benito Marcote, Calvin Leung, Paul Scholz, A. Gopinath, Kendrick M. Smith, A. Keimpema, Shriharsh P. Tendulkar, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010504 meteorology & atmospheric sciences, High-energy astronomy, Linear polarization, Fast radio burst, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), LOFAR, Astrophysics, 01 natural sciences, symbols.namesake, Neutron star, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Faraday effect, symbols, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Circular polarization, 0105 earth and related environmental sciences
Abstract

FRB 20180916B is a well-studied repeating fast radio burst source. Its proximity (~150 Mpc), along with detailed studies of the bursts, have revealed many clues about its nature -- including a 16.3-day periodicity in its activity. Here we report on the detection of 18 bursts using LOFAR at 110-188 MHz, by far the lowest-frequency detections of any FRB to date. Some bursts are seen down to the lowest-observed frequency of 110 MHz, suggesting that their spectra extend even lower. These observations provide an order-of-magnitude stronger constraint on the optical depth due to free-free absorption in the source's local environment. The absence of circular polarization and nearly flat polarization angle curves are consistent with burst properties seen at 300-1700 MHz. Compared with higher frequencies, the larger burst widths (~40-160 ms at 150 MHz) and lower linear polarization fractions are likely due to scattering. We find ~2-3 rad/m^2 variations in the Faraday rotation measure that may be correlated with the activity cycle of the source. We compare the LOFAR burst arrival times to those of 38 previously published and 22 newly detected bursts from the uGMRT (200-450 MHz) and CHIME/FRB (400-800 MHz). Simultaneous observations show 5 CHIME/FRB bursts when no emission is detected by LOFAR. We find that the burst activity is systematically delayed towards lower frequencies by ~3 days from 600 MHz to 150 MHz. We discuss these results in the context of a model in which FRB 20180916B is an interacting binary system featuring a neutron star and high-mass stellar companion., Accepted for publication by ApJL

Published
2021
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10. The 60 pc environment of FRB 20180916B

Author

Shriharsh P. Tendulkar, Mubdi Rahman, Zsolt Paragi, K. Nimmo, Victoria M. Kaspi, T. Joseph W. Lazio, Aida Yu. Kirichenko, Jason W. T. Hessels, Benito Marcote, P. Scholz, P. Chawla, Cees Bassa, A. Keimpema, Ingrid H. Stairs, Armando Gil de Paz, Mohit Bhardwaj, F. Kirsten, Kiyoshi Masui, Emmanuel Fonseca, Fernando Antonio de Ávila, Daniel Reverte Payá, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Astrofísica, H II region, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, Pulsar, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Fast radio burst, Star formation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Astronomía, Neutron star, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, H-alpha, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Fast Radio Burst FRB 20180916B in its host galaxy SDSS J015800.28+654253.0 at 149 Mpc is by far the closest-known FRB with a robust host galaxy association. The source also exhibits a 16.35-day period in its bursting. Here we present optical and infrared imaging as well as integral field spectroscopy observations of FRB 20180916B with the WFC3 camera on the Hubble Space Telescope and the MEGARA spectrograph on the 10.4-m Gran Telescopio Canarias. The 60-90 milliarcsecond (mas) resolution of the Hubble imaging, along with the previous 2.3-mas localization of FRB 20180916B, allow us to probe its environment with a 30-60 pc resolution. We constrain any point-like star-formation or HII region at the location of FRB 20180916B to have an H$\alpha$ luminosity $L_\mathrm{H\alpha} \lesssim 10^{37}\,\mathrm{erg\,s^{-1}}$ and, correspondingly, constrain the local star-formation rate to be $\lesssim10^{-4}\,\mathrm{M_\odot\,yr^{-1}}$. The constraint on H$\alpha$ suggests that possible stellar companions to FRB 20180916B should be of a cooler, less massive spectral type than O6V. FRB 20180916B is 250 pc away (in projected distance) from the brightest pixel of the nearest young stellar clump, which is $\sim380$\,pc in size (full-width at half maximum). With the typical projected velocities of pulsars, magnetars, or neutron stars in binaries (60-750 km s$^{-1}$), FRB 20180916B would need 800 kyr to 7 Myr to traverse the observed distance from its presumed birth site. This timescale is inconsistent with the active ages of magnetars ($\lesssim10$ kyr). Rather, the inferred age and observed separation are compatible with the ages of high-mass X-ray binaries and gamma-ray binaries, and their separations from the nearest OB associations., Comment: Updated version: Updated Figure 2. 16 pages, 4 figures, 1 table. Published in ApJ Letters. Comments welcome

Published
2021

11. Multi-wavelength view of the close-by GRB 190829A sheds light on gamma-ray burst physics

Author

Om Sharan Salafia, Maria Edvige Ravasio, Jun Yang, Tao An, Monica Orienti, Giancarlo Ghirlanda, Lara Nava, Marcello Giroletti, Prashanth Mohan, Riccardo Spinelli, Yingkang Zhang, Benito Marcote, Giuseppe Cimò, Xuefeng Wu, and Zhixuan Li

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract

Gamma-ray bursts are produced as a result of cataclysmic events such as the collapse of a massive star or the merger of two neutron stars. We monitored the position of the close-by gamma-ray burst GRB~190829A, which originated from a massive star collapse, through very long baseline interferometry (VLBI) observations with the EVN and the VLBA, involving a total of 30 telescopes across 4 continents. We carried out a total of 9 observations between 9 and 117 days after the gamma-ray burst at 5 and 15 GHz, with a typical resolution of few milliarcseconds (mas). We obtained limits on the source size and expansion rate. The limits are in agreement with the size evolution entailed by a detailed modelling of the multi-wavelength light curves with a forward plus reverse shock model, which agrees with the observations across almost 18 orders of magnitude in frequency (including the High Energy Stereoscopic System data at TeV photon energies) and more than 4 orders of magnitude in time. Thanks to the broad, high-cadence coverage of the afterglow, afterglow degeneracies are broken to a large extent, allowing us to capture some unique physical insights: we find a low prompt emission efficiency $\lesssim 10^{-3}$; we constrain the fraction of electrons that are accelerated to relativistic speeds in the forward shock to be $\chi_e, Comment: 35 pages, 30 figures, submitted to ApJL. Supplementay materials at http://doi.org/10.5281/zenodo.6412088

Published
2021
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12. Monitoring the magnetar {SGR} 1935$\mathplus$2154 with the {MAGIC} telescopes

Author

Alicia, L('(o))pez-Oramas, Irene Jim('(e))nez Mart('(i))nez, Tarek, Hassan, John, Hoang, Susumu, Inoue, Acciari, Victor A., Stefano, Ansoldi, Lucio Angelo Antonelli, Axel Arbet Engels, Manuel, Artero, Katsuaki, Asano, Dominik, Baack, Ana, Babic, Andr('(e))s, Baquero, Ulisses Barres de Almeida, Juan Abel Barrio, Ivana, Batkovi('(c)), Josefa Becerra Gonzalez, Wlodek, Bednarek, Lorenzo, Bellizzi, Elisa, Bernardini, Maria-Isabel, Bernardos, Alessio, Berti, Jürgen, Besenrieder, Wrijupan, Bhattacharyya, Ciro, Bigongiari, Adrian, Biland, Oscar, Blanch, Hendrik, Bökenkamp, Giacomo, Bonnoli, Zeljka, Bosnjak, Giovanni, Busetto, Roberto, Carosi, Giovanni, Ceribella, Matteo, Cerruti, Yating, Chai, Ashot, Chilingarian, Stefan, Cikota, Sidika Merve Colak, Eduardo, Colombo, Jose Luis Contreras, Juan, Cortina, Stefano, Covino, Giacomo D( extquotesingle)Amico, Valerio D( extquotesingle)Elia, Paolo Da Vela, Francesco, Dazzi, Alessandro De Angelis, Barbara De Lotto, Manuel, Delfino, Jordi, Delgado, Carlos Delgado Mendez, Davide, Depaoli, Federico Di Pierro, Leonardo Di Venere, Elia Do Souto Espi(~(n))eira, Dijana Dominis Prester, Alice, Donini, Daniela, Dorner, Michele, Doro, Dominik, Elsaesser, Vandad Fallah Ramazani, Alicia, Fattorini, Maria Victoria Fonseca, Lluis, Font, Christian, Fruck, Satoshi, Fukami, Yasushi, Fukazawa, Garc('(i))a L('(o))pez, Ramon J., Markus, Garczarczyk, Sargis, Gasparyan, Markus, Gaug, Giglietto, Nicola, Francesco, Giordano, Pawel, Gliwny, Nikola, Godinovic, David, Green, Jarred Gershon Green, Daniela, Hadasch, Alexander, Hahn, Lea, Heckmann, Javier, Herrera, Dario, Hrupec, Moritz, Hütten, Tomohiro, Inada, Kazuma, Ishio, Yuki, Iwamura, Jenni, Jormanainen, L('(e))a, Jouvin, Marie, Karjalainen, Daniel, Kerszberg, Yukiho, Kobayashi, Hidetoshi, Kubo, Junko, Kushida, Alessandra, Lamastra, Damir, Lelas, Francesco, Leone, Elina, Lindfors, Lena, Linhoff, Saverio, Lombardi, Francesco, Longo, Ruben, Lopez-Coto, Marcos, L('(o))pez-Moya, Loporchio, Serena, Bernardo Machado de Oliveira Fraga, Camilla, Maggio, Pratik, Majumdar, Martin, Makariev, Manuela, Mallamaci, Galina, Maneva, Marina, Manganaro, Karl, Mannheim, Laura, Maraschi, Mos(`(e)), Mariotti, Manel, Martinez, Daniel, Mazin, Stefano, Menchiari, Simone, Mender, Sa( (s))a Mi('(c))anovi('(c)), Davide, Miceli, Tjark, Miener, Jose Miguel Miranda, Razmik, Mirzoyan, Edgar, Molina, Abelardo, Moralejo, Daniel, Morcuende, Victoria, Moreno, Elena, Moretti, Takeshi, Nakamori, Lara, Nava, Vitaly, Neustroev, Cosimo, Nigro, Kari, Nilsson, Kyoshi, Nishijima, Koji, Noda, Seiya, Nozaki, Yoshiki, Ohtani, Tomohiko, Oka, Jorge, Otero-Santos, Simona, Paiano, Michele, Palatiello, David, Paneque, Riccardo, Paoletti, Paredes, Josep M., Lovro, Pavleti('(c)), Pablo, Pe(~(n))il, Massimo, Persic, Marine, Pihet, Pier Giorgio Prada Moroni, Elisa, Prandini, Chaitanya, Priyadarshi, Ivica, Puljak, Wolfgang, Rhode, Marc, Rib('(o)), Javier, Rico, Chiara, Righi, Andrea, Rugliancich, Narek, Sahakyan, Takayuki, Saito, Shunsuke, Sakurai, Konstancja, Satalecka, Francesco Gabriele Saturni, Bernd, Schleicher, Kevin, Schmidt, Thomas, Schweizer, Julian, Sitarek, Iva, ( (S))nidari('(c)), Dorota, Sobczy('(n))ska, Alessia, Spolon, Antonio, Stamerra, Jelena Stri( (s))kovi('(c)), Derek, Strom, Marcel, Strzys, Yusuke, Suda, Tihomir, Suri('(c)), Mitsunari, Takahashi, Ryuji, Takeishi, Fabrizio, Tavecchio, Petar, Temnikov, Tomislav, Terzic, Masahiro, Teshima, Luca, Tosti, Stefano, Truzzi, Antonio, Tutone, Santiago, Ubach, Juliane van Scherpenberg, Gaia, Vanzo, Monica VAZQUEZ ACOSTA, Sofia, Ventura, Vassil, Verguilov, Carlo Francesco Vigorito, Vincenzo, Vitale, Ievgen, Vovk, Martin, Will, Carolin, Wunderlich, Tokonatsu, Yamamoto, Darko, Zari('(c)), Filippo, Ambrosino, Alice, Borghese, Francesco Coti Zelati, Hessels, Jason W. T., Franz, Kirsten, Benito, Marcote, Ould-Boukattine, Omar S., Alessandro, Papitto, and Snelders and, Mark P.

Published
2021

13. The extreme colliding-wind system Apep: resolved imagery of the central binary and dust plume in the infrared

Author

Joseph R. Callingham, Peredur M. Williams, Peter G. Tuthill, R. M. Lau, A. Soulain, Y. Han, Benito Marcote, Benjamin J. S. Pope, and Paul A. Crowther

Subjects
Proper motion, media_common.quotation_subject, Binary number, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Wind speed, Pinwheel, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), media_common, Physics, Orbital elements, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astronomy and Astrophysics, Plume, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sky, Outflow, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The recent discovery of a spectacular dust plume in the system 2XMM J160050.7-514245 (referred to as "Apep") suggested a physical origin in a colliding-wind binary by way of the "Pinwheel" mechanism. Observational data pointed to a hierarchical triple-star system, however several extreme and unexpected physical properties seem to defy the established physics of such objects. Most notably, a stark discrepancy was found in the observed outflow speed of the gas as measured spectroscopically in the line-of-sight direction compared to the proper motion expansion of the dust in the sky plane. This enigmatic behaviour arises at the wind base within the central Wolf-Rayet binary: a system that has so far remained spatially unresolved. Here we present an updated proper motion study deriving the expansion speed of Apep's dust plume over a two-year baseline that is four times slower than the spectroscopic wind speed, confirming and strengthening the previous finding. We also present the results from high-angular-resolution near-infrared imaging studies of the heart of the system, revealing a close binary with properties matching a Wolf-Rayet colliding-wind system. Based on these new observational constraints, an improved geometric model is presented yielding a close match to the data, constraining the orbital parameters of the Wolf-Rayet binary and lending further support to the anisotropic wind model., Comment: This article has been accepted for publication in the Monthly Notices of the Royal Astronomical Society. 17 pages, 9 figures, 6 tables

Published
2020

14. Two Wolf-Rayet stars at the heart of colliding-wind binary Apep

Author

Y. Han, Benito Marcote, Benjamin J. S. Pope, Joseph R. Callingham, Peredur M. Williams, Peter G. Tuthill, and Paul A. Crowther

Subjects
Milky Way, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Stellar classification, 01 natural sciences, Spectral line, Wind speed, Momentum, Wolf–Rayet star, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Colliding-wind binary, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - High Energy Astrophysical Phenomena
Abstract

Infrared imaging of the colliding-wind binary Apep has revealed a spectacular dust plume with complicated internal dynamics that challenges standard colliding-wind binary physics. Such challenges can be potentially resolved if a rapidly-rotating Wolf-Rayet star is located at the heart of the system, implicating Apep as a Galactic progenitor system to long-duration gamma-ray bursts. One of the difficulties in interpreting the dynamics of Apep is that the spectral composition of the stars in the system was unclear. Here we present visual to near-infrared spectra that demonstrate that the central component of Apep is composed of two classical Wolf-Rayet stars of carbon- (WC8) and nitrogen-sequence (WN4-6b) subtypes. We argue that such an assignment represents the strongest case of a classical WR+WR binary system in the Milky Way. The terminal line-of-sight wind velocities of the WC8 and WN4-6b stars are measured to be $2100 \pm 200$ and $3500 \pm 100$ km s$^{-1}$, respectively. If the mass-loss rate of the two stars are typical for their spectral class, the momentum ratio of the colliding winds is expected to be $\approx$ 0.4. Since the expansion velocity of the dust plume is significantly smaller than either of the measured terminal velocities, we explore the suggestion that one of the Wolf-Rayet winds is anisotropic. We can recover a shock-compressed wind velocity consistent with the observed dust expansion velocity if the WC8 star produces a significantly slow equatorial wind with a velocity of $\approx$530 km s$^{-1}$. Such slow wind speeds can be driven by near-critical rotation of a Wolf-Rayet star., Accepted for publication in MNRAS, 10 pages, 9 figures, 1 table

Published
2020

15. Cygnus X-1 contains a 21-solar mass black hole-Implications for massive star winds

Author

Sera Markoff, Lijun Gou, Jerome A. Orosz, Arash Bahramian, Victoria Grinberg, A. Rushton, Xueying Zheng, Janusz Ziółkowski, Benito Marcote, Mark J. Reid, Do-Young Byun, Richard Dodson, Gregory R. Sivakoff, X. H. Zhao, Jeong-Sook Kim, Coenraad J. Neijssel, Phil Uttley, Valeriu Tudose, Ilya Mandel, James Miller-Jones, Maria Rioja, David M. Russell, Taehyun Jung, Thomas J. Maccarone, Alexandra J. Tetarenko, Joern Wilms, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Solar mass, Multidisciplinary, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrometry, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Star (graph theory), Compact star, 01 natural sciences, Black hole, Stellar wind, Stars, General Relativity and Quantum Cosmology, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010306 general physics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We use radio astrometry to refine the distance to the black hole X-ray binary Cygnus X-1, which we find to be $2.22^{+0.18}_{-0.17}$ kiloparsecs. When combined with previous optical data, this implies a black hole mass of $21.2\pm2.2$ solar masses, higher than previous measurements. The formation of such a high-mass black hole in a high-metallicity system constrains wind mass loss from massive stars., Published online in Science on 2021 February 18; Main (3 figures; 1 Table) + Supplementary (11 figures; 3 Tables)

Published
2020

16. FRB 121102 Bursts Show Complex Time-Frequency Structure

Author

Cees Bassa, Liam Connor, Julia Deneva, J. M. Cordes, Jason W. T. Hessels, Andrew Seymour, V. M. Kaspi, Fronefield Crawford, Shami Chatterjee, Maura McLaughlin, Vishal Gajjar, Ben Stappers, D. Michilli, Scott M. Ransom, Geoffrey C. Bower, Emily Petroff, Laura Spitler, K. Gourdji, Casey J. Law, Zsolt Paragi, Shriharsh P. Tendulkar, Benito Marcote, Anne M. Archibald, A. Keimpema, P. Scholz, Ryan S. Lynch, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
010504 meteorology & atmospheric sciences, Non-thermal [radiation mechanisms], Astrophysics::High Energy Astrophysical Phenomena, radio continuum: general, FOS: Physical sciences, Astrophysics, 01 natural sciences, General [radio continuum], Dwarf [Galaxies], 0103 physical sciences, Dispersion (optics), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Envelope (waves), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Nebula, Fast radio burst, Astronomy and Astrophysics, galaxies: dwarf, radiation mechanisms: non-thermal, Secular variation, Pulse (physics), Space and Planetary Science, Stochastic drift, Radio frequency, Astrophysics - High Energy Astrophysical Phenomena
Abstract

FRB 121102 is the only known repeating fast radio burst source. Here we analyze a wide-frequency-range (1-8 GHz) sample of high-signal-to-noise, coherently dedispersed bursts detected using the Arecibo and Green Bank telescopes. These bursts reveal complex time-frequency structures that include sub-bursts with finite bandwidths. The frequency-dependent burst structure complicates the determination of a dispersion measure (DM); we argue that it is appropriate to use a DM metric that maximizes frequency-averaged pulse structure, as opposed to peak signal-to-noise, and find DM = 560.57 +/- 0.07 pc/cc at MJD 57644. After correcting for dispersive delay, we find that the sub-bursts have characteristic frequencies that typically drift lower at later times in the total burst envelope. In the 1.1-1.7 GHz band, the ~ 0.5-1-ms sub-bursts have typical bandwidths ranging from 100-400 MHz, and a characteristic drift rate of ~ 200 MHz/ms towards lower frequencies. At higher radio frequencies, the sub-burst bandwidths and drift rate are larger, on average. While these features could be intrinsic to the burst emission mechanism, they could also be imparted by propagation effects in the medium local to the source. Comparison of the burst DMs with previous values in the literature suggests an increase of Delta(DM) ~ 1-3 pc/cc in 4 years, though this could be a stochastic variation as opposed to a secular trend. This implies changes in the local medium or an additional source of frequency-dependent delay. Overall, the results are consistent with previously proposed scenarios in which FRB 121102 is embedded in a dense nebula., Comment: Submitted to ApJ; comments welcome

Published
2019
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17. Resolving the Decades-long Transient FIRST J141918.9+394036: An Orphan Long Gamma-Ray Burst or a Young Magnetar Nebula?

Author

Om Sharan Salafia, Emily Petroff, K. Nimmo, Benito Marcote, Jason W. T. Hessels, Zsolt Paragi, Ramesh Karuppusamy, High Energy Astrophys. & Astropart. Phys (API, FNWI), ITA, DEU, and NLD

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Nebula, European VLBI Network, 010504 meteorology & atmospheric sciences, Fast radio burst, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Magnetar, 01 natural sciences, Afterglow, law.invention, Telescope, 13. Climate action, Space and Planetary Science, law, 0103 physical sciences, Very-long-baseline interferometry, Gamma-ray burst, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Ofek (2017) identified FIRST J141918.9+394036 (hereafter FIRST J1419+3940) as a radio source sharing similar properties and host galaxy type to the compact, persistent radio source associated with the first known repeating fast radio burst, FRB 121102. Law et al. (2018) showed that FIRST J1419+3940 is a transient source decaying in brightness over the last few decades. One possible interpretation is that FIRST J1419+3940 is a nearby analogue to FRB 121102 and that the radio emission represents a young magnetar nebula (as several scenarios assume for FRB 121102). Another interpretation is that FIRST J1419+3940 is the afterglow of an `orphan' long gamma-ray burst (GRB). The environment is similar to where most such events are produced. To distinguish between these hypotheses, we conducted radio observations using the European VLBI Network at 1.6 GHz to spatially resolve the emission and to search for millisecond-duration radio bursts. We detect FIRST J1419+3940 as a compact radio source with a flux density of $620 \pm 20\ \mathrm{\mu Jy}$ (on 2018 September 18) and a source size of $3.9 \pm 0.7\ \mathrm{mas}$ (i.e. $1.6 \pm 0.3\ \mathrm{pc}$ given the angular diameter distance of $83\ \mathrm{Mpc}$). These results confirm that the radio emission is non-thermal and imply an average expansion velocity of $(0.10 \pm 0.02)c$. Contemporaneous high-time-resolution observations using the 100-m Effelsberg telescope detected no millisecond-duration bursts of astrophysical origin. The source properties and lack of short-duration bursts are consistent with a GRB jet expansion, whereas they disfavor a magnetar birth nebula., Comment: 8 pages, 4 figures, accepted for publication in ApJL

Published
2019

18. A direct localization of a fast radio burst and its host

Author

Jason W. T. Hessels, Matthew W. Abruzzo, Michael P. Rupen, H. J. van Langevelde, Scott M. Ransom, Paul Demorest, Sarah Burke-Spolaor, Bryan J. Butler, Zsolt Paragi, P. Scholz, Shami Chatterjee, Benito Marcote, V. M. Kaspi, Maura McLaughlin, A. Keimpema, Slavko Bogdanov, Laura Spitler, Andrew Seymour, Geoffrey C. Bower, C. G. Bassa, James M. Cordes, T. J. W. Lazio, Robert Wharton, Casey J. Law, Shriharsh P. Tendulkar, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, X-shaped radio galaxy, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Nebula, Multidisciplinary, 010308 nuclear & particles physics, Fast radio burst, Canadian Hydrogen Intensity Mapping Experiment, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Galaxy, Interstellar medium, Neutron star, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Fast radio bursts are astronomical radio flashes of unknown physical nature with durations of milliseconds. Their dispersive arrival times suggest an extragalactic origin and imply radio luminosities orders of magnitude larger than any other kind of known short-duration radio transient. Thus far, all FRBs have been detected with large single-dish telescopes with arcminute localizations, and attempts to identify their counterparts (source or host galaxy) have relied on contemporaneous variability of field sources or the presence of peculiar field stars or galaxies. These attempts have not resulted in an unambiguous association with a host or multi-wavelength counterpart. Here we report the sub-arcsecond localization of FRB 121102, the only known repeating burst source, using high-time-resolution radio interferometric observations that directly image the bursts themselves. Our precise localization reveals that FRB 121102 originates within 100 mas of a faint 180 uJy persistent radio source with a continuum spectrum that is consistent with non-thermal emission, and a faint (25th magnitude) optical counterpart. The flux density of the persistent radio source varies by tens of percent on day timescales, and very long baseline radio interferometry yields an angular size less than 1.7 mas. Our observations are inconsistent with the fast radio burst having a Galactic origin or its source being located within a prominent star-forming galaxy. Instead, the source appears to be co-located with a low-luminosity active galactic nucleus or a previously unknown type of extragalactic source. [Truncated] If other fast radio bursts have similarly faint radio and optical counterparts, our findings imply that direct sub-arcsecond localizations of FRBs may be the only way to provide reliable associations., Nature, published online on 4 Jan 2017, DOI: 10.1038/nature20797

Published
2017
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19. Simultaneous X-Ray and Radio Observations of the Repeating Fast Radio Burst FRB ∼ 180916.J0158+65

Author

M. Rafiei-Ravandi, V. M. Kaspi, Jason W. T. Hessels, F. Kirsten, K. Nimmo, T. Cassanelli, Charles J. Naudet, J. Mena-Parra, Benito Marcote, Kendrick M. Smith, Keith Vanderlinde, Jonathon Kocz, Ingrid H. Stairs, A. Naidu, A. Cook, Paul Scholz, Ramesh Karuppusamy, A. Josephy, Bryan Gaensler, Kiyoshi Masui, Ziggy Pleunis, Aaron B. Pearlman, D. Michilli, Kevin Bandura, Calvin Leung, P. Chawla, Laura Spitler, Mubdi Rahman, Kyung-Hoon Shin, M. Merryfield, A. Yu. Kirichenko, M. Cruces, Mohit Bhardwaj, Walid A. Majid, Thomas A. Prince, Shriharsh P. Tendulkar, Deborah C. Good, A. Keimpema, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010504 meteorology & atmospheric sciences, Fast radio burst, Astrophysics::High Energy Astrophysical Phenomena, Canadian Hydrogen Intensity Mapping Experiment, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Redshift, Luminosity, Radio telescope, Neutron star, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Fermi Gamma-ray Space Telescope
Abstract

We report on simultaneous radio and X-ray observations of the repeating fast radio burst source FRB 180916.J0158+65 using the Canadian Hydrogen Intensity Mapping Experiment (CHIME), Effelsberg, and Deep Space Network (DSS-14 and DSS-63) radio telescopes and the Chandra X-ray Observatory. During 33 ks of Chandra observations, we detect no radio bursts in overlapping Effelsberg or Deep Space Network observations and a single radio burst during CHIME/FRB source transits. We detect no X-ray events in excess of the background during the Chandra observations. These non-detections imply a 5-$��$ limit of $, 16 pages, 2 figures, submitted to ApJ

Published
2020
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20. Localizations of Fast Radio Bursts on milliarcsecond scales

Author

Zsolt Paragi and Benito Marcote

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, European VLBI Network, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Magnetar, Pulsar wind nebula, Neutron star, Supernova, Pulsar, Astrophysics::Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Supernova remnant, Astrophysics::Galaxy Astrophysics
Abstract

Fast Radio Bursts (FRBs) are transient sources that emit a single radio pulse with a duration of only a few milliseconds. Since the discovery of the first FRB in 2007, tens of similar events have been detected. However, their physical origin remains unclear, and a number of scenarios even larger than the number of known FRBs has been proposed during these years. The presence of repeating bursts in FRB 121102 allowed us to perform a precise localization of the source with the Very Large Array and the European VLBI Network (EVN). Optical observations with Keck, Gemini and HST unveiled the host to be a low-metallicity star-forming dwarf galaxy located at a redshift of 0.193. The EVN results showed that the bursts are co-located (within a projected separation of $< 40$ pc) to a compact and persistent radio source with a size of $< 0.7$ pc inside a star-forming region. This environment resembles the ones where superluminous supernovae (SLSNe) or long gamma-ray bursts are produced. Although the nature of this persistent source and the origin of the bursts remain unknown, scenarios considering a pulsar/magnetar energizing a young SLSN, or a system with a pulsar/magnetar in the vicinity of a massive black hole are the most plausible ones to date. More recent observations have shown that the bursts from FRB 121102 are almost 100% linearly polarized at an unexpectedly high and variable Faraday rotation measure, that has been observed to date only in vicinities of massive black holes. The bursts are thus likely produced from a neutron star in such environment, although the system can still be explained by a young neutron star embedded in a highly magnetized nebula. Upcoming interferometric searches are expected to report tens of these localizations in the coming years, unveil if this source is representative of the whole population or a particular case, and dramatically boosting the field of FRBs., 11 pages, 3 figures, proceedings of the 14th European VLBI Network Symposium & Users Meeting, held on 8-11 October 2018 in Granada, Spain

Published
2019
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21. Compact radio emission indicates a structured jet was produced by a binary neutron star merger

Author

Marcello Giroletti, Leonid I. Gurvits, Benito Marcote, Gianpiero Tagliaferri, C. Reynolds, Gabriele Ghisellini, J. Moldon, Miguel A. Pérez-Torres, Lara Nava, Peter G. Jonker, Tao An, Stefano Covino, Sándor Frey, Valerio D'Elia, Jun Yang, Zsolt Paragi, E. Chassande-Mottin, Albino Perego, H. J. van Langevelde, M. G. Bernardini, Ruben Salvaterra, S. D. Vergani, Om Sharan Salafia, A. Melandri, Jay Blanchard, Robert Beswick, Carolina Casadio, M. Branchesi, Marcin P. Gawronski, G. Ghirlanda, Sergio Campana, Monica Colpi, Tiziana Venturi, Minghua Zhang, P. D'Avanzo, Ivan Agudo, Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Ghirlanda, G, Salafia, O, Paragi, Z, Giroletti, M, Yang, J, Marcote, B, Blanchard, J, Agudo, I, An, T, Bernardini, M, Beswick, R, Branchesi, M, Campana, S, Casadio, C, Chassande-Mottin, E, Colpi, M, Covino, S, D'Avanzo, P, D'Elia, V, Frey, S, Gawronski, M, Ghisellini, G, Gurvits, L, Jonker, P, Van Langevelde, H, Melandri, A, Moldon, J, Nava, L, Perego, A, Perez-Torres, M, Reynolds, C, Salvaterra, R, Tagliaferri, G, Venturi, T, Vergani, S, Zhang, M, Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Governo Italiano, Agenzia Spaziale Italiana, European Commission, Ministerio de Economía y Competitividad (España), Ministry of Science and Technology of the People's Republic of China, Hungarian Scientific Research Fund, Australian Government, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), ITA, GBR, FRA, DEU, ESP, AUS, TWN, NLD, SWE, and HUN

Subjects
radiation: electromagnetic, neutron star: binary, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, gravitational radiation: direct detection, 01 natural sciences, 7. Clean energy, Electromagnetic radiation, electromagnetic field: production, jet: relativistic, Astrophysical Jets, Gamma Ray Bursts, Very Long Baseline Interferometry, Gravitational Waves, Kilonova, Radio telescope, FIS/05 - ASTRONOMIA E ASTROFISICA, 0103 physical sciences, Very-long-baseline interferometry, detector: resolution, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Jet (fluid), Multidisciplinary, 010308 nuclear & particles physics, Gravitational wave, gravitational radiation, gravitational radiation detector, Afterglow, Neutron star, gravitational radiation: emission, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Outflow, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The binary neutron star merger event GW170817 was detected through both electromagnetic radiation and gravitational waves. Its afterglow emission may have been produced by either a narrow relativistic jet or an isotropic outflow. High-spatial-resolution measurements of the source size and displacement can discriminate between these scenarios. We present very-long-baseline interferometry observations, performed 207.4 days after the merger by using a global network of 32 radio telescopes. The apparent source size is constrained to be smaller than 2.5 milli-arc seconds at the 90% confidence level. This excludes the isotropic outflow scenario, which would have produced a larger apparent size, indicating that GW170817 produced a structured relativistic jet. Our rate calculations show that at least 10% of neutron star mergers produce such a jet.© 2019 The Authors, some rights reserved. All rights reserved., The National Institute of Astrophysics is is acknowledged for PRIN-grant (2017) 1.05.01.88.06. The Italian Ministry for University and Research (MIUR) is acknowledged through the project >FIGARO> (Prin-MIUR) grant 1.05.06.13. ASI is acknowledged for grant I/004/11/3. The research leading to these results has received funding from the European Commission Horizon 2020 Research and Innovation Programme under grant agreement 730562 (RadioNet). The Spanish Ministerio de Economa y Competitividad (MINECO) is acknowledged for financial support under grants AYA201676012-C3-1-P, FPA2015-69210-C6-2-R, and MDM-2014-0369 of ICCUB (Unidad de Excelencia >Mara de Maeztu>). M.A.P.-T. acknowledges support from the Spanish MINECO through grants AYA2012-38491-C02-02 and AYA2015-63939-C2-1-P.T.A. is supported by the National Key R&D Programme of China (2018YFA0404603). E.C.-M. acknowledges support from the European Union's Horizon 2020 research and innovation program under grant agreement 653477. S.F. thanks the Hungarian National Research, Development and Innovation Office (OTKA NN110333) for support. The Long Baseline Array is part of the Australia Telescope National Facility, which is funded by the Australian Government for operation as a National Facility managed by CSIRO.

Published
2019
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22. Probing the origin of the off-pulse emission from the pulsars B0525+21 and B2045-16

Author

Zsolt Paragi, Benito Marcote, Yogesh Maan, and A. Keimpema

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), European VLBI Network, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rms noise, 01 natural sciences, Pulse (physics), Pulsar, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Pulsars typically exhibit radio emission in the form of narrow pulses originated from confined regions of their magnetospheres. A potential presence of magnetospherically originated emission outside this region, the so-called off-pulse emission, would challenge the existing theories. Detection of significant off-pulse emission has been reported so far from only two pulsars, B0525+21 and B2045-16, at 325 and 610 MHz. However, the nature of this newly uncovered off-pulse emission remains unclear. To probe its origin we conducted very high resolution radio observations of B0525+21 and B2045-16 with the European VLBI Network (EVN) at 1.39 GHz. Whereas the pulsed emission is detected at a level consistent with previous observations, we report absence of any off-pulse emission above $42$ and $96\ \mathrm{\mu Jy\ beam^{-1}}$ (three times the rms noise levels) for B0525+21 and B2045-16, respectively. Our stringent upper limits imply the off-pulse emission to be less than $0.4$ and $0.3\%$ of the period-averaged pulsed flux density, i.e., much fainter than the previously suggested values of $1$-$10\%$. Since the EVN data are most sensitive to extremely compact angular scales, our results suggest a non-magnetospheric origin for the previously reported off-pulse emission. Presence of extended emission that is resolved out on these milliarcsecond scales still remains plausible. In this case, we constrain the emission to arise from structures with sizes of $\sim (0.61$-$19) \times 10^3\ \mathrm{au}$ for B0525+21 and $\sim (0.48$-$8.3) \times 10^3\ \mathrm{au}$ for B2045-16. These constraints might indicate that the two pulsars are accompanied by compact bow-shock pulsar wind nebulae. Future observations probing intermediate angular scales ($\sim 0.1$-$5\ \mathrm{arcsec}$) will help in clarifying the actual origin of the off-pulse emission., Comment: 6 pages, 4 figures, accepted for publication as a Letter in A&A

Published
2019
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23. An extreme magneto-ionic environment associated with the fast radio burst source FRB 121102

Author

George Heald, F. Fernandez, Laura Spitler, Elizabeth A. K. Adams, Daniele Michilli, Robert Wharton, Casey Brinkman, P. J. Van Rooy, Geoffrey C. Bower, Vishal Gajjar, Gregory Hellbourg, Charlotte Sobey, Benito Marcote, T. J. W. Lazio, Casey J. Law, D. Whitlow, A. Seymour, Shriharsh P. Tendulkar, Scott M. Ransom, C. G. Bassa, V. M. Kaspi, Andrew Siemion, Maura McLaughlin, R. S. Lynch, James M. Cordes, Paul Demorest, K. Gourdji, Zsolt Paragi, Jason W. T. Hessels, Anne M. Archibald, Shami Chatterjee, Natasha Maddox, P. Scholz, Slavko Bogdanov, High Energy Astrophys. & Astropart. Phys (API, FNWI), API Other Research (FNWI), and Astronomy

Subjects
POLARIZATION, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, SAGITTARIUS-A-ASTERISK, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Supernova remnant, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Nebula, Multidisciplinary, 010308 nuclear & particles physics, Fast radio burst, Canadian Hydrogen Intensity Mapping Experiment, FARADAY-ROTATION, FIELDS, Redshift, Black hole, CRAB-NEBULA, Neutron star, Crab Nebula, GAMMA-RAY, HOST GALAXY, SUPERNOVA REMNANT, BLACK-HOLE, X-RAY, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Fast radio bursts (FRBs) are millisecond-duration, extragalactic radio flashes of unknown physical origin. FRB 121102, the only known repeating FRB source, has been localized to a star-forming region in a dwarf galaxy at redshift z = 0.193, and is spatially coincident with a compact, persistent radio source. The origin of the bursts, the nature of the persistent source, and the properties of the local environment are still debated. Here we present bursts that show ~100% linearly polarized emission at a very high and variable Faraday rotation measure in the source frame: RM_src = +1.46 x 10^5 rad m^-2 and +1.33 x 10^5 rad m^-2 at epochs separated by 7 months, in addition to narrow (< 30 mus) temporal structure. The large and variable rotation measure demonstrates that FRB 121102 is in an extreme and dynamic magneto-ionic environment, while the short burst durations argue for a neutron star origin. Such large rotation measures have, until now, only been observed in the vicinities of massive black holes (M_BH > 10^4 MSun). Indeed, the properties of the persistent radio source are compatible with those of a low-luminosity, accreting massive black hole. The bursts may thus come from a neutron star in such an environment. However, the observed properties may also be explainable in other models, such as a highly magnetized wind nebula or supernova remnant surrounding a young neutron star., Published in Nature: DOI: 10.1038/nature25149

Published
2018

24. Multi-epoch VLBI of a double maser super burst

Author

Huib Jan van Langevelde, Stan Kurtz, N. N. Shakhvorostova, Georgij Rudnitskii, Jay Blanchard, M. Olech, Todd R. Hunter, L. N. Volvach, K. Immer, Ross A. Burns, Gabor Orosz, Irina Val‘tts, Willem A. Baan, G. C. MacLeod, Crystal L. Brogan, Olga Bayandina, B. Kramer, Tomoya Hirota, Kee-Tae Kim, James O. Chibueze, Benito Marcote, A. E. Volvach, Gabriele Surcis, ITA, DEU, AUS, KOR, JPN, MEX, NLD, POL, CHN, ZAF, and RUS

Subjects
Physics, Epoch (reference date), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, law.invention, Orders of magnitude (time), Astrophysics - Solar and Stellar Astrophysics, law, Astrophysics of Galaxies (astro-ph.GA), Very-long-baseline interferometry, Astrophysics::Solar and Stellar Astrophysics, Maser, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

In a rare and spectacular display, two well-known massive star forming regions, W49N and G25.65+1.05, recently underwent maser 'super burst' - their fluxes suddenly increasing above 30,000 and 18,000 Jy, respectively, reaching several orders of magnitude above their usual values. In quick-response, ToO observations with the EVN, VLBA and KaVA were obtained constituting a 4 week campaign - producing a high-cadence multi-epoch VLBI investigation of the maser emission. The combination of high-resolution, polarisation and flux monitoring during the burst provides one of the best accounts, to date, of the maser super burst phenomenon, aiding their use as astrophysical tools. These proceedings contain the preliminary results of our campaign.

Published
2018
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25. Constraining very-high-energy and optical emission from FRB 121102 with the MAGIC telescopes

Author

D. Elsaesser, Satoshi Masuda, Alessandra Lamastra, A. Hahn, Stefano Covino, K. Nishijima, Francesco Longo, Kazumi Kashiyama, Arka Chatterjee, Marc Ribó, Pierre Colin, D. Hadasch, J. Becerra González, Oscar Blanch, Julian Sitarek, P. Bangale, Abelardo Moralejo, Hidetoshi Kubo, W. Bhattacharyya, W. Rhode, J. Kushida, Jose Luis Contreras, J. Rico, P. Giammaria, Laura Spitler, F. Leone, M. Minev, L. Maraschi, E. Colombo, Juan Cortina, I. Puljak, Masahiro Teshima, G. Ferrara, Jordi Delgado, M. Vazquez Acosta, M. López, G. Bonnoli, J. Palacio, T. Schweizer, E. Molina, Victoria Moreno, Chiara Righi, J. M. Paredes, Antonio Stamerra, M. Delfino, Francesco Dazzi, A. Fernández-Barral, Jason W. T. Hessels, N. Torres-Albà, B. Banerjee, C. Arcaro, J. R. Garcia, Darko Zarić, P. Da Vela, Iva Šnidarić, D. Baack, D. Ninci, Jürgen Besenrieder, Alicia Fattorini, D. Dominis Prester, F. Di Pierro, M. Peresano, M. Makariev, A. Arbet Engels, Vitaly Neustroev, Lab Saha, Luca Foffano, Pablo Peñil, R. J. García López, Stefano Gallozzi, Jose Miguel Miranda, A. Somero, V. D'Elia, Aaron Dominguez, A. Niedzwiecki, J. E. Ward, C. Fruck, Ciro Bigongiari, Kari Nilsson, P. Majumdar, C. Nigro, G. Ceribella, Elina Lindfors, Juan Abel Barrio, L. Nogués, D. Dorner, M. Nievas Rosillo, M. Mariotti, S. M. Colak, M. Garczarczyk, D. Guberman, Kohta Murase, A. Rugliancich, Marina Manganaro, V. Fallah Ramazani, C. Maggio, G. Maneva, Daniel Mazin, Tomislav Terzić, Dario Hrupec, R. Paoletti, A. Berti, M. Will, A. López-Oramas, D. Paneque, N. Godinović, B. De Lotto, K. Mannheim, Tarek M. Hassan, W. Bednarek, Andrew Seymour, G. Pedaletti, Shimpei Tsujimoto, P. Cumani, Konstancja Satalecka, Michele Doro, Fabrizio Tavecchio, M. I. Martínez, Massimo Persic, V. A. Acciari, Ll. Font, Razmik Mirzoyan, P G Prada Moroni, Adrian Biland, Louis Antonelli, D. Lelas, G. Vanzo, E. Moretti, Ana Babić, Sabrina Einecke, A. De Angelis, Tihomir Surić, S. Paiano, K. Ishio, Dorota Sobczyńska, Benito Marcote, Stefano Ansoldi, D. Fidalgo, Markus Gaug, M. V. Fonseca, Saverio Lombardi, John Hoang, Takashi Saito, U. Barres de Almeida, Elisa Prandini, Rodolfo Carosi, Susumu Inoue, Daniele Michilli, Y. Iwamura, M. Strzys, D. Kuveždić, I. Vovk, Valentí Bosch-Ramon, Jose Carlos Herrera, Petar Temnikov, Koji Noda, Elisa Bernardini, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Arcaro, C., Baack, D., Babić, A., Banerjee, B., Bangale, P., de Almeida, U. Barre, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Ceribella, G., Chatterjee, A., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Domínguez, A., Prester, D. Domini, Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Ramazani, V. Fallah, Fattorini, A., Fernández-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Gallozzi, S., López, R. J. García, Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Kubo, H., Kushida, J., Kuveždić, D., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Oramas, A., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Moreno, V., Moretti, E., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nieva, Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Peñil, P., Peresano, M., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Garcia, J. R., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Somero, A., Stamerra, A., Strzys, M., Surić, T., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tsujimoto, S., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Ward, J. E., Will, M., Zarić, D., Marcote, B., Spitler, L. G., Hessels, J. W. T., Kashiyama, K., Murase, K., Bosch-Ramon, V., Michilli, D., Seymour, A., Universitat de Barcelona, and ITA

Subjects
High energy, Photon, Radiation mechanisms: non-thermal, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Radiació, Raigs gamma, radiation mechanisms: non-thermal, methods: data analysis, methods: observational, gamma-rays: general, Methods: observational, Methods: data analysis, 0103 physical sciences, Gamma ray astronomy, Astronomia de raigs gamma, observational [Methods], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Millisecond, general [Gamma-rays], ta115, Radiation, non-thermal [Radiation mechanisms], 010308 nuclear & particles physics, Gamma rays, Gamma ray, Astronomy and Astrophysics, Astronomy and Astrophysic, Galaxy, Redshift, data analysi [Methods], Wavelength, 13. Climate action, Space and Planetary Science, Gamma-rays: general, ddc:520, Física nuclear, Optical emission spectroscopy, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Fast radio bursts (FRBs) are bright flashes observed typically at GHz frequencies with millisecond duration, whose origin is likely extragalactic. Their nature remains mysterious, motivating searches for counterparts at other wavelengths. FRB 121102 is so far the only source known to repeatedly emit FRBs and is associated with a host galaxy at redshift $z \simeq 0.193$. We conducted simultaneous observations of FRB 121102 with the Arecibo and MAGIC telescopes during several epochs in 2016--2017. This allowed searches for millisecond-timescale burst emission in very-high-energy (VHE) gamma rays as well as the optical band. While a total of five FRBs were detected during these observations, no VHE emission was detected, neither of a persistent nature nor burst-like associated with the FRBs. The average integral flux upper limits above 100 GeV at 95% confidence level are $6.6 \times 10^{-12}~\mathrm{photons\ cm^{-2}\ s^{-1}}$ (corresponding to luminosity $L_{\rm VHE} \lesssim 10^{45}~\mathrm{erg\ s^{-1}}$) over the entire observation period, and $1.2 \times 10^{-7}~ \mathrm{photons\ cm^{-2}\ s^{-1}}$ ($L_{\rm VHE} \lesssim 10^{49}~\mathrm{erg\ s^{-1}}$) over the total duration of the five FRBs. We constrain the optical U-band flux to be below 8.6 mJy at 5-$\sigma$ level for 1-ms intervals around the FRB arrival times. A bright burst with U-band flux $29~\mathrm{mJy}$ and duration $\sim 12$ ms was detected 4.3 s before the arrival of one FRB. However, the probability of spuriously detecting such a signal within the sampled time space is 1.5% (2.2 $\sigma$, post-trial), i.e. consistent with the expected background. We discuss the implications of the obtained upper limits for constraining FRB models., Comment: 9 pages, 3 figures. Accepted for publication in MNRAS the 2nd September 2018

Published
2018
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26. In quest of non-thermal signatures in early-type stars

Author

Josep M. Paredes, Benito Marcote, X. Paredes-Fortuny, Pedro L. Luque-Escamilla, Jorge Casares, Marc Ribó, Josep Martí, and Jorge Núñez

Subjects
NRAO VLA Sky Survey, Physics, education.field_of_study, Astrophysics::High Energy Astrophysical Phenomena, Milky Way, Population, Astrophysics::Instrumentation and Methods for Astrophysics, Flare star, Astronomy, White dwarf, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star count, Cherenkov Telescope Array, Stars, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, education, Astrophysics::Galaxy Astrophysics
Abstract

A reduced fraction of luminous, early-type stars in binaries has provided some of the most interesting sources in modern high-energy astrophysics. A fingerprint of the capability of these systems to accelerate particles up to TeV energies is the associated detection of non-thermal, synchrotron emission often in the radio domain. Here we aim to identify new early-type, luminous stars where energetic, non-thermal processes are at work to enable future comparative studies based on an extended sample. Moreover, these objects also appear as very interesting targets for future gamma-ray observatories such as the Cherenkov Telescope Array. We have designed a methodology to search for new examples of these interesting sources in order to enlarge the extremely reduced population currently known. Our search procedure is described in this paper, together with a practical application using public databases and catalogues currently available (Luminous Stars in the Northern Milky Way, NRAO VLA Sky Survey, and Westerbork Northern Sky Survey). Optical and radio interferometric follow-up observations of selected candidate stars were conducted to better assess their properties. Although no new discoveries of this kind have been achieved yet, the observational data analyzed in this work does provide some interesting side results, such as characterizing the spectroscopic and photometric properties of two early-type stars originally selected as candidates to be explored, namely TYC4051-1277-1 and TYC3594-2269-1. Unexpectedly, this last one was also found to be a new DAO-type white dwarf star instead of a non-degenerate star. In addition, both stars seem to display different optical periods based on our photometric monitoring.

Published
2015
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27. MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

Author

A. De Angelis, A. Treves, Vitaly Neustroev, R. Zanin, Adrian Biland, J. Rico, G. Maneva, Dario Hrupec, Thomas Bretz, M. Palatiello, Dario Gasparrini, I. Lozano, M. A. Lopez, A. González Muñoz, Louis Antonelli, Walter Max-Moerbeck, Diego F. Torres, Jelena Aleksić, R. López-Coto, X. Paredes-Fortuny, A. Niedzwiecki, D. Nakajima, Julian Sitarek, Francesco Dazzi, A. Fernández-Barral, Patrick Vogler, P. Munar-Adrover, J. M. Paredes, J. Kushida, Jose Luis Contreras, Masahiro Teshima, Ivica Puljak, Filippo D'Ammando, Daniela Dorner, K. Mallot, Wolfgang Rhode, Pierre Colin, R. J. García López, Elina Lindfors, A. Sillanpää, Juan Abel Barrio, David Paneque, Juan Cortina, C. Fruck, M. Gaug, D. Fidalgo, T. Toyama, Antonio Stamerra, Daniel Mazin, Takashi Saito, J. Krause, W. Bednarek, J. Herrera, B. De Lotto, Fabrizio Tavecchio, Julia Thaele, S. N. Shore, K. Berger, Ll. Font, Koji Noda, Reiko Orito, Elisa Bernardini, J. Hose, I. Snidaric, J. L. Richards, D. Elsaesser, E. de Oña Wilhelmi, Francesco Longo, H. Takami, Abelardo Moralejo, K. Nishijima, F. Di Pierro, C. Delgado Mendez, D. Dominis Prester, T. Steinbring, Massimo Persic, Yusuke Konno, Juri Poutanen, E. Lorenz, M. Hayashida, Stefano Covino, G. De Caneva, M. V. Fonseca, Kari Nilsson, K. Kodani, Y. Hanabata, K. Saito, G. Bonnoli, Talvikki Hovatta, M. Will, Marc Ribó, D. Tescaro, P. Antoranz, Konstancja Satalecka, R. Reinthal, P. Temnikov, Michele Doro, M. L. Knoetig, S. Buson, Razmik Mirzoyan, Hidetoshi Kubo, P. G. Prada Moroni, D. Garrido Terrats, Damir Lelas, V. Scalzotto, Nikola Godinovic, Benito Marcote, Dorota Sobczyńska, Oscar Blanch, Ana Babić, P. Da Vela, Stefano Ansoldi, T. Schweizer, Riccardo Paoletti, E. Prandini, F. Borracci, Alessandro Carosi, D. Hadasch, Jose Miguel Miranda, C. Schultz, V. Scapin, Anthony C. S. Readhead, M. Strzys, L. Maraschi, B. Biasuzzi, Tomislav Terzić, D. Galindo, M. I. Martínez, P. Bangale, Sabrina Einecke, S. R. Gozzini, J. Rodriguez Garcia, M. Makariev, U. Menzel, W. Idec, E. Colombo, L. O. Takalo, Mosè Mariotti, A.-K. Overkemping, Saverio Lombardi, Hanna Kellermann, K. Frantzen, V. Kadenius, S. Bonnefoy, S. Paiano, Karl Mannheim, D. Eisenacher, E. Carmona, Markus Garczarczyk, Alicia López-Oramas, Natalia Lewandowska, A. La Barbera, M. Nievas Rosillo, J. Becerra González, Aalto-yliopisto, Aalto University, Aleksi , J., Ansoldi, Stefano, Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., de Ona Wilhelmi, E., Delgado Mendez, C., Di Pierro, F., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fernandez Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., Garcia Lopez, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Godinovi , N., Gonzalez Munoz, A., Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, Francesco, Lopez, M., Lopez Coto, R., Lopez Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martinez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar Adrover, P., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribo, M., Rico, J., Rodriguez Garcia, J., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpaa, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzi , T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Will, M., Zanin, R., Berger, K., Buson, S., D'Ammando, F., Gasparrini, D., Hovatta, T., Max Moerbeck, W., Readhead, A., and Richards, J.

Subjects
radiation mechanisms: non-thermal, galaxies: active, BL Lacertae objects: individual: 1ES 0806+524, galaxies: jets, gamma rays: galaxies, Astrophysics::High Energy Astrophysical Phenomena, astro-ph.GA, galaxies: active, jets [galaxies], Flux, FOS: Physical sciences, radiation mechanisms: non-thermal, BL Lacertae objects: individual: 1ES 0806+524, galaxies: jets, gamma rays: galaxies, individual: 1ES 0806+524 [BL Lacertae objects], Astrophysics, law.invention, law, MAGIC (telescope), Blazar, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, ta115, ta213, Compton scattering, Astronomy, Astronomy and Astrophysics, non-thermal [radiation mechanisms], non-thermal, galaxies: active, BL Lacertae objects: individual: 1ES 0806+524, galaxies: jets, gamma rays: galaxies [radiation mechanisms], Astrophysics - Astrophysics of Galaxies, Galaxies: active, Galaxies: jets, Gamma rays: galaxies, Radiation mechanisms: non-thermal, Space and Planetary Science, Crab Nebula, Astrophysics of Galaxies (astro-ph.GA), active [galaxies], galaxies [gamma rays], ddc:520, Spectral energy distribution, Astrophysics - High Energy Astrophysical Phenomena, BL Lac object, Flare
Abstract

Monthly notices of the Royal Astronomical Society 451(1), 739 - 750 (2015). doi:10.1093/mnras/stv895, The high-frequency-peaked BL Lac (HBL) 1ES 0806+524 (z = 0.138) was discovered in very high energy (VHE) γ-rays in 2008. Until now, the broad-band spectrum of 1ES 0806+524 has been only poorly characterized, in particular at high energies. We analysed multiwavelength observations from γ-rays to radio performed from 2011 January to March, which were triggered by the high activity detected at optical frequencies. These observations constitute the most precise determination of the broad-band emission of 1ES 0806+524 to date. The stereoscopic Major Atmospheric Gamma-Ray Imaging Cherenkov (MAGIC) observations yielded a γ-ray signal above 250 GeV of (3.7 ± 0.7) per cent of the Crab Nebula flux with a statistical significance of 9.9σ. The multiwavelength observations showed significant variability in essentially all energy bands, including a VHE γ-ray flare that lasted less than one night, which provided unprecedented evidence for short-term variability in 1ES 0806+524. The spectrum of this flare is well described by a power law with a photon index of 2.97 ± 0.29 between ∼150 GeV and 1 TeV and an integral flux of (9.3 ± 1.9) per cent of the Crab nebula flux above 250 GeV. The spectrum during the non-flaring VHE activity is compatible with the only available VHE observation performed in 2008 with VERITAS when the source was in a low optical state. The broad-band spectral energy distribution can be described with a one-zone synchrotron self-Compton model with parameters typical for HBLs, indicating that 1ES 0806+524 is not substantially different from the HBLs previously detected., Published by Oxford Univ. Press, Oxford

Published
2015
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28. Simultaneous X-Ray, Gamma-Ray, and Radio Observations of the Repeating Fast Radio Burst FRB 121102

Author

Maura McLaughlin, Geoffrey C. Bower, Benito Marcote, K. Gourdji, Zsolt Paragi, Cees Bassa, James M. Cordes, V. M. Kaspi, Casey J. Law, Scott M. Ransom, Shriharsh P. Tendulkar, Shami Chatterjee, Robert Wharton, Jason W. T. Hessels, Sarah Burke-Spolaor, Bryan J. Butler, Slavko Bogdanov, Andrew Seymour, P. Scholz, Laura Spitler, Ryan S. Lynch, D. Michilli, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, X-rays: general, 01 natural sciences, Radio telescope, stars: neutron, Observatory, 0103 physical sciences, X-rays: bursts, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Fast radio burst, Canadian Hydrogen Intensity Mapping Experiment, Astronomy and Astrophysics, gamma rays: general, 3. Good health, Neutron star, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract

We undertook coordinated campaigns with the Green Bank, Effelsberg, and Arecibo radio telescopes during Chandra X-ray Observatory and XMM-Newton observations of the repeating fast radio burst FRB 121102 to search for simultaneous radio and X-ray bursts. We find 12 radio bursts from FRB 121102 during 70 ks total of X-ray observations. We detect no X-ray photons at the times of radio bursts from FRB 121102 and further detect no X-ray bursts above the measured background at any time. We place a 5$\sigma$ upper limit of $3\times10^{-11}$ erg cm$^{-2}$ on the 0.5--10 keV fluence for X-ray bursts at the time of radio bursts for durations $, Comment: 13 pages, 5 figures, published in ApJ

Published
2017

29. MAGIC upper limits on the GRB 090102 afterglow

Author

M. Gaug, Elisa Bernardini, Gianluca Giavitto, A. González Muñoz, C. Delgado Mendez, Victor Stamatescu, T. Schweizer, A. De Angelis, Mosè Mariotti, A.-K. Overkemping, D. Dominis Prester, Robert Wagner, L. A. Antonelli, Julian Sitarek, Saverio Lombardi, M. L. Knoetig, P. Antoranz, J. Hose, Natalia Lewandowska, T. Toyama, A. Sillanpää, Nikola Godinovic, Takashi Saito, P. Temnikov, Benito Marcote, Abelardo Moralejo, A. La Barbera, Fabrizio Tavecchio, M. V. Fonseca, A. Bouvier, J. Moldón, D. Garrido Terrats, Konstancja Satalecka, Ll. Font, Reiko Orito, Francisco Prada, W. Idec, Julia Thaele, Michele Doro, M. Palatiello, Dario Hrupec, Jelena Aleksić, M. A. Lopez, E. Colombo, P. Da Vela, V. Scalzotto, Dominik Elsaesser, U. Barres de Almeida, A. Niedzwiecki, M. Doert, Damir Lelas, Fabio Zandanel, Ralph Bock, L. O. Takalo, K. Frantzen, Q. Weitzel, Tihomir Surić, M. Uellenbeck, David Paneque, Francesco Dazzi, Patrick Vogler, Hiroyasu Tajima, I. Snidaric, D. Carreto Fidalgo, Ana Babić, Dorota Sobczyńska, G. De Caneva, U. Menzel, M. Salvati, Stefano Ansoldi, S. Rügamer, Juan Abel Barrio, Riccardo Paoletti, Nina Nowak, Diego F. Torres, A. Herrero, Christian Fruck, S. Partini, M. Hayashida, Francesco Longo, E. Lorenz, S. Paiano, Kari Nilsson, Karl Mannheim, Nijil Mankuzhiyil, K. Berger, P. Munar-Adrover, I. Lozano, D. Hadasch, Giacomo Bonnoli, E. Prandini, J. M. Paredes, M. Garczarczyk, Antonio Stamerra, Silvia Preziuso, Marc Ribó, P. G. Prada Moroni, J. Kushida, Aldo Treves, Jose Luis Contreras, J. Krause, B. De Lotto, Masahiro Teshima, O. Tibolla, Juan Cortina, Martin Makariev, Oscar Blanch, Tomislav Terzić, A. Hadamek, J. Storz, Ivica Puljak, Alicia López-Oramas, Pierre Colin, J. Becerra González, Emanuele Paolo Farina, S. Bonnefoy, Aaron Dominguez, Mario Meucci, R. Mirzoyan, D. Eisenacher, E. Carmona, Daniel Ferenc, Thomas Bretz, S. N. Shore, Wlodek Bednarek, Alessandro Carosi, Ruben Lopez-Coto, Felix Spanier, D. Nakajima, C. Schultz, V. Scapin, Jose Miguel Miranda, F. Borracci, Wolfgang Rhode, Ignasi Reichardt, G. Maneva, R. Zanin, A. Saggion, Adrian Biland, J. Rico, R. Reinthal, L. Maraschi, Elina Lindfors, Daniel Mazin, K. Mallot, R. J. García López, Stefano Covino, S. Sun, Massimo Persic, A. Boller, L. Cossio, D. Tescaro, T. Krähenbühl, K. Saito, J. Masbou, M. I. Martínez, V. Kadenius, S. R. Gozzini, J. Rodriguez Garcia, Daniela Dorner, J., Aleksic, S., Ansoldi, L. A., Antonelli, P., Antoranz, A., Babic, U. B., de Almeida, J. A., Barrio, J. B., Gonzalez, W., Bednarek, K., Berger, E., Bernardini, A., Biland, O., Blanch, R. K., Bock, A., Boller, S., Bonnefoy, G., Bonnoli, F., Borracci, T., Bretz, E., Carmona, A., Carosi, D. C., Fidalgo, P., Colin, E., Colombo, J. L., Contrera, J., Cortina, L., Cossio, S., Covino, P., Da Vela, F., Dazzi, A., De Angeli, G., De Caneva, B., De Lotto, C. D., Mendez, M., Doert, A., Dominguez, D. D., Prester, D., Dorner, M., Doro, D., Eisenacher, D., Elsaesser, E., Farina, D., Ferenc, M. V., Fonseca, L., Font, K., Frantzen, C., Fruck, R. J. G., Lopez, M., Garczarczyk, D. G., Terrat, M., Gaug, G., Giavitto, N., Godinovic, A. G., Munoz, S. R., Gozzini, A., Hadamek, D., Hadasch, A., Herrero, J., Hose, D., Hrupec, W., Idec, V., Kadeniu, M. L., Knoetig, T., Krahenbuhl, J., Krause, J., Kushida, A. L., Barbera, D., Lela, N., Lewandowska, E., Lindfor, S., Lombardi, R., Lopez Coto, M., Lopez, A., Lopez Orama, E., Lorenz, I., Lozano, M., Makariev, K., Mallot, G., Maneva, N., Mankuzhiyil, K., Mannheim, L., Maraschi, B., Marcote, M., Mariotti, M., Martinez, J., Masbou, D., Mazin, U., Menzel, M., Meucci, J. M., Miranda, R., Mirzoyan, J., Moldon, A., Moralejo, P., Munar Adrover, D., Nakajima, A., Niedzwiecki, K., Nilsson, N., Nowak, R., Orito, A., Overkemping, S., Paiano, M., Palatiello, D., Paneque, R., Paoletti, J. M., Parede, S., Partini, M., Persic, F., Prada, P. G. P., Moroni, E., Prandini, S., Preziuso, I., Puljak, I., Reichardt, R., Reinthal, W., Rhode, M., Ribo, J., Rico, J. R., Garcia, S., Rugamer, A., Saggion, K., Saito, T., Saito, M., Salvati, K., Satalecka, V., Scalzotto, V., Scapin, C., Schultz, T., Schweizer, S. N., Shore, A., Sillanpaa, J., Sitarek, I., Snidaric, D., Sobczynska, F., Spanier, V., Stamatescu, A., Stamerra, J., Storz, S., Sun, T., Suric, L., Takalo, F., Tavecchio, P., Temnikov, T., Terzic, D., Tescaro, M., Teshima, J., Thaele, O., Tibolla, D. F., Torre, T., Toyama, A., Treve, M., Uellenbeck, P., Vogler, R. M., Wagner, Q., Weitzel, F., Zandanel, R., Zanin, A., Bouvier, M., Hayashida, H., Tajima, and Longo, Francesco

Subjects
Photon, General, Non-thermal - gamma-ray burst, Radiation mechanisms, Astrophysics::High Energy Astrophysical Phenomena, gamma-ray burst: general, Hadron, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, general [gamma-ray burst], 7. Clean energy, 01 natural sciences, law.invention, Telescope, law, 0103 physical sciences, MAGIC (telescope), 010306 general physics, 010303 astronomy & astrophysics, Cherenkov radiation, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Physics, ta115, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, radiation mechanisms: non-thermal, non-thermal [radiation mechanisms], Afterglow, gamma-rays bursts: general, Space and Planetary Science, ddc:520, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Gamma-ray burst, Fermi Gamma-ray Space Telescope
Abstract

Indications of a GeV component in the emission from GRBs are known since the EGRET observations during the 1990's and they have been confirmed by the data of the Fermi satellite. These results have, however, shown that our understanding of GRB physics is still unsatisfactory. The new generation of Cherenkov observatories and in particular the MAGIC telescope, allow for the first time the possibility to extend the measurement of GRBs from several tens up to hundreds of GeV energy range. Both leptonic and hadronic processes have been suggested to explain the possible GeV/TeV counterpart of GRBs. Observations with ground-based telescopes of very high energy photons (E>30 GeV) from these sources are going to play a key role in discriminating among the different proposed emission mechanisms, which are barely distinguishable at lower energies. MAGIC telescope observations of the GRB 090102 (z=1.547) field and Fermi Large Area Telescope (LAT) data in the same time interval are analysed to derive upper limits of the GeV/TeV emission. We compare these results to the expected emissions evaluated for different processes in the framework of a relativistic blast wave model for the afterglow. Simultaneous upper limits with Fermi and a Cherenkov telescope have been derived for this GRB observation. The results we obtained are compatible with the expected emission although the difficulties in predicting the HE and VHE emission for the afterglow of this event makes it difficult to draw firmer conclusions. Nonetheless, MAGIC sensitivity in the energy range of overlap with space-based instruments (above about 40 GeV) is about one order of magnitude better with respect to Fermi. This makes evident the constraining power of ground-based observations and shows that the MAGIC telescope has reached the required performance to make possible GRB multiwavelength studies in the very high energy range., 8 pages, 5 figures, 2 tables. Submitted to MNRAS

Published
2014
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30. Very-high-energy gamma-ray observations of the Type Ia Supernova SN 2014J with the MAGIC telescopes

Author

K. Mallot, F. Di Pierro, Francesco Longo, R. J. García López, D. Hadasch, Daniela Dorner, U. Barres de Almeida, Damir Lelas, S. Paiano, Karl Mannheim, W. Idec, Mosè Mariotti, Dariusz Gora, Gaia Vanzo, D. Nakajima, D. Elsaesser, Dorota Sobczyńska, P. Da Vela, M. Gaug, Arka Chatterjee, R. Zanin, Adrian Biland, Saverio Lombardi, Abelardo Moralejo, Wlodek Bednarek, Alessandro Carosi, Max Ludwig Ahnen, J. Becerra González, M. Palatiello, M. Hayashida, Ruben Lopez-Coto, J. Herrera, D. Fidalgo, Martin Makariev, Pratik Majumdar, M. V. Fonseca, Massimo Persic, Alessio Berti, Marc Ribó, P. Bangale, Hidetoshi Kubo, E. Moretti, Alexander Hahn, Dario Hrupec, M. A. Lopez, Francesco Dazzi, A. Fernández-Barral, M. Vazquez Acosta, J. Rico, I. Reichardt, Rodolfo Carosi, Oscar Blanch, E. Colombo, P. Giammaria, P. Temnikov, Gareth Hughes, J. M. Paredes, L. Nogués, B. Biasuzzi, Koji Noda, Stefano Covino, U. Menzel, Antonio Stamerra, K. Kodani, L. O. Takalo, Elisa Bernardini, Kyoshi Nishijima, Nikola Godinovic, Benito Marcote, Jose Miguel Miranda, E. Prandini, L. Perri, Yusuke Konno, Diego F. Torres, M. Doert, M. H. Wu, L. A. Antonelli, M. I. Martínez, M. Garczarczyk, A. La Barbera, Marcel Strzys, S. Bonnefoy, Julian Sitarek, D. Eisenacher Glawion, X. Paredes-Fortuny, M. Peresano, D. Dominis Prester, Sabrina Einecke, B. De Lotto, Kari Nilsson, D. Tescaro, J. Hose, A. Niedzwiecki, C. Fruck, M. Engelkemeier, F. Borracci, M. Nievas Rosillo, M. Will, A. De Angelis, A. Treves, Vitaly Neustroev, R. Mirzoyan, T. Toyama, Fabrizio Tavecchio, T. Surić, J. R. Garcia, David Paneque, A. Sillanpää, Ll. Font, S. Schroeder, Giacomo Bonnoli, L. Maraschi, D. Guberman, D. Garrido Terrats, Ivica Puljak, Pierre Colin, I. Snidaric, V. Fallah Ramazani, Elina Lindfors, Takashi Saito, G. Maneva, J. Palacio, J. E. Ward, Masahiro Teshima, Daniel Mazin, Juan Abel Barrio, E. de Oña Wilhelmi, Ievgen Vovk, Aaron Dominguez, Stefano Ansoldi, P. G. Prada Moroni, T. Schweizer, Riccardo Paoletti, Tomislav Terzić, Marina Manganaro, Ana Babić, D. Galindo, B. Banerjee, C. Arcaro, Juri Poutanen, J. Kushida, G. Pedaletti, Thomas Bretz, Jose Luis Contreras, P. Antoranz, P. Cumani, Konstancja Satalecka, Michele Doro, Juan Cortina, Wolfgang Rhode, K. Frantzen, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Arcaro, C., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Berti, Alessio, Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carosi, R., Carosi, A., Chatterjee, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Onã Wilhelmi, E., DI Pierro, F., Doert, M., Domã­nguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Engelkemeier, M., Fallah Ramazani, V., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C, Galindo, D., Garciá López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinoviä , N., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, Lã³pez, M., López Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martã­nez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Noguã©s, L., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Peresano, M., Perri, L., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribã³, M., Rico, J., Saito, T., Satalecka, K., Schroeder, S., Schweizer, T., Sillanpaã¤, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Strzys, M., Suriä , T., Takalo, L., Tavecchio, F., Temnikov, P., Terziä , T., Tescaro, D., Teshima, M., Torres, D. F., Toyama, T., Treves, A., Vanzo, G., Vazquez Acosta, M., Vovk, I., Ward, J. E., Will, M., Wu, M. H., and Zanin, R.

Subjects
Individual: SN 2014J [Supernovae], Gamma rays: General, Supernovae: Individual: SN 2014J, Astronomy and Astrophysics, Space and Planetary Science, air, Astrophysics::High Energy Astrophysical Phenomena, Hadron, VHE [gamma ray], FOS: Physical sciences, Astrophysics, Type (model theory), power spectrum, 01 natural sciences, 0103 physical sciences, supernova, MAGIC (telescope), 010303 astronomy & astrophysics, Cherenkov radiation, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Spectral index, 010308 nuclear & particles physics, photon, Gamma ray, imaging, General [Gamma rays], Astronomy and Astrophysic, MAGIC, gamma rays: general, supernovae: individual (SN 2014J), flux, Supernova, Cherenkov counter, ddc:520, high [energy], Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing)
Abstract

In this work we present data from observations with the MAGIC telescopes of SN 2014J detected in January 21 2014, the closest Type Ia supernova since Imaging Air Cherenkov Telescopes started to operate. We probe the possibility of very-high-energy (VHE; $E\geq100$ GeV) gamma rays produced in the early stages of Type Ia supernova explosions. We performed follow-up observations after this supernova explosion for 5 days, between January 27 and February 2 in 2014. We search for gamma-ray signal in the energy range between 100 GeV and several TeV from the location of SN 2014J using data from a total of $\sim5.5$ hours of observations. Prospects for observing gamma-rays of hadronic origin from SN 2014J in the near future are also being addressed. No significant excess was detected from the direction of SN 2014J. Upper limits at 95$\%$ confidence level on the integral flux, assuming a power-law spectrum, d$F/$d$E\propto E^{-\Gamma}$, with a spectral index of $\Gamma=2.6$, for energies higher than 300 GeV and 700 GeV, are established at $1.3\times10^{-12}$ and $4.1\times10^{-13}$ photons~cm$^{-2}$s$^{-1}$, respectively. For the first time, upper limits on the VHE emission of a Type Ia supernova are established. The energy fraction isotropically emitted into TeV gamma rays during the first $\sim10$ days after the supernova explosion for energies greater than 300 GeV is limited to $10^{-6}$ of the total available energy budget ($\sim 10^{51}$ erg). Within the assumed theoretical scenario, the MAGIC upper limits on the VHE emission suggest that SN 2014J will not be detectable in the future by any current or planned generation of Imaging Atmospheric Cherenkov Telescopes., Comment: 5 pages, 2 figures. Accepted for publication in A&A

Published
2017
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31. FRB 121102 is coincident with a star forming region in its host galaxy

Author

Scott M. Ransom, Victoria M. Kaspi, Sarah Burke-Spolaor, Casey J. Law, Bryan J. Butler, H. J. van Langevelde, Zsolt Paragi, Geoffrey C. Bower, Jason W. T. Hessels, James M. Cordes, Shriharsh P. Tendulkar, Shami Chatterjee, Benito Marcote, Laura Spitler, Slavko Bogdanov, Elizabeth A. K. Adams, P. Scholz, Cees Bassa, Natasha Maddox, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Stellar mass, 010308 nuclear & particles physics, Fast radio burst, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Supernova, Neutron star, Spitzer Space Telescope, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Gamma-ray burst, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract

We present optical, near- and mid-infrared imaging of the host galaxy of FRB 121102 with the Gemini North telescope, the Hubble Space Telescope and the Spitzer Space Telescope. The FRB 121102 host galaxy is resolved, revealing a bright star forming region located in the outskirts of the irregular, low-metallicity dwarf galaxy. The star forming region has a half-light radius of 0.68 kpc (0.20 arcsec), encompassing the projected location of the compact (, 6 pages, 2 figures, submitted to ApJL; v2 has correct r' band magnitude

Published
2017
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32. Review on the multiwavelength emission of the gamma-ray binary LS I +61 303

Author

Benito Marcote

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), High energy, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Binary number, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Star (graph theory), Compact star, Neutron star, Pulsar, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract

Gamma-ray binaries are systems composed of a massive star and a compact object that produce emission from radio to very high energy gamma-rays. LS I +61 303 is one of the only six gamma-ray binaries discovered so far. It is thought that gamma-ray binaries contain a young highly rotating neutron star as compact object, and the emission is produced by the interaction between its relativistic pulsar wind and the stellar wind, However, in the case of LS I +61 303 a microquasar scenario is still considered and results pointing to oppose directions have been published during the last decades. Here we provide a review about the state of the art of LS I +61 303, summarizing the observed emission from radio to very high energy gamma-rays along all these years, and we discuss the proposed scenarios that can explain such emission., Comment: 9 pages to be published in the proceedings of XII Multifrequency Behaviour of High Energy Cosmic Sources Workshop, Palermo (Italy), PoS(MULTIF2017)045

Published
2017
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33. The Repeating Fast Radio Burst FRB 121102 as Seen on Milliarcsecond Angular Scales

Author

Benito Marcote, Paragi, Z., Hessels, J. W. T., Keimpema, A., Langevelde, H. J., Huang, Y., Bassa, C. G., Bogdanov, S., Bower, G. C., Burke-Spolaor, S., Butler, B. J., Campbell, R. M., Chatterjee, S., Cordes, J. M., Demorest, P., Garrett, M. A., Ghosh, T., Kaspi, V. M., Law, C. J., Lazio, T. J. W., Mclaughlin, M. A., Ransom, S. M., Salter, C. J., Scholz, P., Seymour, A., Siemion, A., Spitler, L. G., Tendulkar, S. P., Wharton, R. S., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
radio continuum: galaxies, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, techniques: high angular resolution, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, radiation mechanisms: non-thermal, astro-ph.CO, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics, astro-ph.IM
Abstract

The millisecond-duration radio flashes known as Fast Radio Bursts (FRBs) represent an enigmatic astrophysical phenomenon. Recently, the sub-arcsecond localization (~ 100mas precision) of FRB121102 using the VLA has led to its unambiguous association with persistent radio and optical counterparts, and to the identification of its host galaxy. However, an even more precise localization is needed in order to probe the direct physical relationship between the millisecond bursts themselves and the associated persistent emission. Here we report very-long-baseline radio interferometric observations using the European VLBI Network and the 305-m Arecibo telescope, which simultaneously detect both the bursts and the persistent radio emission at milliarcsecond angular scales and show that they are co-located to within a projected linear separation of < 40pc (< 12mas angular separation, at 95% confidence). We detect consistent angular broadening of the bursts and persistent radio source (~ 2-4mas at 1.7GHz), which are both similar to the expected Milky Way scattering contribution. The persistent radio source has a projected size constrained to be < 0.7pc (< 0.2mas angular extent at 5.0GHz) and a lower limit for the brightness temperature of T_b > 5 x 10^7K. Together, these observations provide strong evidence for a direct physical link between FRB121102 and the compact persistent radio source. We argue that a burst source associated with a low-luminosity active galactic nucleus or a young neutron star energizing a supernova remnant are the two scenarios for FRB121102 that best match the observed data., 13 pages, 5 figures, accepted to ApJL

Published
2017
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34. Investigating the peculiar emission from the new VHE gamma-ray source H1722+119

Author

M. Hayashida, M. Makariev, B. Biasuzzi, K. Mallot, R. J. García López, Louis Antonelli, D. Dominis Prester, E. Prandini, M. Doert, M. H. Wu, Massimo Persic, F. D'Ammando, Marc Ribó, G. Bonnoli, Abelardo Moralejo, Juri Poutanen, R. Reinthal, V. Fallah Ramazani, P. Bangale, Y. Hanabata, Razmik Mirzoyan, U. Barres de Almeida, Damir Lelas, T. Steinbring, Marina Manganaro, P. G. Prada Moroni, Stefano Covino, Hidetoshi Kubo, P. Antoranz, D. Galindo, J. Becerra González, G. Pedaletti, Dorota Sobczyńska, D. Nakajima, Thomas Bretz, J. Hose, Andrei Berdyugin, Pratik Majumdar, M. V. Fonseca, S. Bonnefoy, A. Sillanpää, Arka Chatterjee, Francesco Longo, D. Elsaesser, F. Di Pierro, K. Kodani, Alexander Hahn, Konstancja Satalecka, Walter Max-Moerbeck, Tomoki Saito, D. Tescaro, Ivica Puljak, Pierre Colin, H. Takami, L. Nogués, U. Menzel, Michele Doro, M. I. Martínez, Gareth Hughes, Talvikki Hovatta, C. Schultz, E. Moretti, Marcel Strzys, D. Fidalgo, Vassil Verguilov, Aaron Dominguez, Diego F. Torres, Julia Thaele, E. de Oña Wilhelmi, Reiko Orito, F. Verrecchia, Sabrina Einecke, Junko Kushida, P. Da Vela, R. López-Coto, J. Rodriguez Garcia, J. E. Ward, M. Palatiello, Elina Lindfors, A. Niedzwiecki, Kyoshi Nishijima, Ievgen Vovk, Wolfgang Rhode, Daniel Mazin, Oscar Blanch, Julian Sitarek, Juan Abel Barrio, L. Maraschi, Francesco Dazzi, David Paneque, A. Fernández-Barral, Markus Garczarczyk, Yusuke Konno, C. Fruck, B. De Lotto, M. Villata, T. Schweizer, T. Toyama, D. Guberman, Tomislav Terzić, K. Frantzen, J. L. Richards, Mosè Mariotti, A.-K. Overkemping, S. Paiano, Saverio Lombardi, Karl Mannheim, D. Hadasch, L. Perri, A. La Barbera, D. Eisenacher Glawion, X. Paredes-Fortuny, P. Temnikov, M. Nievas Rosillo, W. Idec, A. González Muñoz, E. Colombo, B. Banerjee, S. Buson, L. O. Takalo, Masahiro Teshima, Daniela Dorner, R. Zanin, Dariusz Gora, Adrian Biland, M. Gaug, J. Rico, J. Herrera, Koji Noda, Elisa Bernardini, A. De Angelis, A. Treves, Vitaly Neustroev, Jose Luis Contreras, Juan Cortina, G. Maneva, C. M. Raiteri, Nikola Godinovic, Benito Marcote, Max Ludwig Ahnen, Kari Nilsson, P. Giammaria, M. Will, Dario Hrupec, M. A. Lopez, R. Clavero, D. Garrido Terrats, W. Bednarek, Fabrizio Tavecchio, Ll. Font, I. Snidaric, Ana Babić, Stefano Ansoldi, Riccardo Paoletti, J. Palacio, J. M. Paredes, Antonio Stamerra, Alessandro Carosi, Jose Miguel Miranda, F. Borracci, Anthony C. S. Readhead, Universitat de Barcelona, Aalto-yliopisto, Aalto University, Ahnen ML, Ansoldi S, Antonelli LA, Antoranz P, Babic A, Banerjee B, Bangale P, de Almeida UB, Barrio JA, Gonzalez JB, Bednarek W, Bernardini E, Biasuzzi B, Biland A, Blanch O, Bonnefoy S, Bonnoli G, Borracci F, Bretz T, Buson S, Carosi A, Chatterjee A, Clavero R, Colin P, Colombo E, Contreras JL, Cortina J, Covino S, Da Vela P, Dazzi F, De Angelis A, De Lotto B, Wilhelmi ED, Di Pierro F, Doert M, Dominguez A, Prester DD, Dorner D, Doro M, Einecke S, Glawion DE, Elsaesser D, Ramazani VF, Fernandez-Barral A, Fidalgo D, Fonseca MV, Font L, Frantzen K, Fruck C, Galindo D, Lopez RJG, Garczarczyk M, Terrats DG, Gaug M, Giammaria P, Godinovic N, Munoz AG, Gora D, Guberman D, Hadasch D, Hahn A, Hanabata Y, Hayashida M, Herrera J, Hose J, Hrupec D, Hughes G, Idec W, Kodani K, Konno Y, Kubo H, Kushida J, La Barbera A, Lelas D, Lindfors E, Lombardi S, Longo F, Lopez M, Lopez-Coto R, Majumdar P, Makariev M, Mallot K, Maneva G, Manganaro M, Mannheim K, Maraschi L, Marcote B, Mariotti M, Martinez M, Mazin D, Menzel U, Miranda JM, Mirzoyan R, Moralejo A, Moretti E, Nakajima D, Neustroev V, Niedzwiecki A, Rosillo MN, Nilsson K, Nishijima K, Noda K, Nogues L, Orito R, Overkemping A, Paiano S, Palacio J, Palatiello M, Paneque D, Paoletti R, Paredes JM, Paredes-Fortuny X, Pedaletti G, Perri L, Persic M, Poutanen J, Moroni PGP, Prandini E, Puljak I, Rhode W, Ribo M, Rico J, Garcia JR, Saito T, Satalecka K, Schultz C, Schweizer T, Sillanpaa A, Sitarek J, Snidaric I, Sobczynska D, Stamerra A, Steinbring T, Strzys M, Takalo L, Takami H, Tavecchio F, Temnikov P, Terzic T, Tescaro D, Teshima M, Thaele J, Torres DF, Toyama T, Treves A, Verguilov V, Vovk I, Ward JE, Will M, Wu MH, Zanin R, DAmmando F, Berdyugin A, Hovatta T, Max-Moerbeck W, Raiteri CM, Readhead ACS, Reinthal R, Richards JL, Verrecchia F, Villata M, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Buson, S., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Oña Wilhelmi, E., Di Pierro, F., Doert, M., Domínguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Fallah Ramazani, V., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinović, N., González Muñoz, A., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Nogués, L., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Perri, L., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Saito, T., Satalecka, K., Schultz, C., Schweizer, T., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T, Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., D'Ammando, F., Berdyugin, A., Hovatta, T., Max Moerbeck, W., Raiteri, C. M., Readhead, A. C. S., Reinthal, R., Richards, J. L., Verrecchia, F., and Villata, M.

Subjects
galaxie [Gamma-rays], gamma-rays: galaxies, UPGRADE, Astrophysics, DETECTED BLAZARS, 01 natural sciences, LARGE-AREA TELESCOPE, law.invention, Raigs gamma, law, galaxies: active, BL Lacertae objects: individual: H1722+119, galaxies, distances and redshifts, BL LACERTAE OBJECTS, ALL-SKY SURVEY, MAGIC, TELESCOPES, LAC OBJECTS, SOURCE CATALOG, MAJOR, HELICAL JETS, CRAB-NEBULA, MAGIC (telescope), 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), distances and redshift [Galaxies], active BL Lacertae objects, individual, H1722+119 galaxies, distances and redshifts gamma-rays, Galaxies: active, Galaxies: distances and redshifts, Gamma-rays: galaxies, Astronomy and Astrophysics, Space and Planetary Science, galaxies [Gamma-rays], Extragalactic background light, Spectral energy distribution, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, BL Lac object, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Owens Valley Radio Observatory, Astrophysics::Cosmology and Extragalactic Astrophysics, Telescope, galaxies: active, BL Lacertae objects: individual: H1722+119, galaxies: distances and redshifts, gamma-rays: galaxies, 0103 physical sciences, individual: H1722+119 [BL Lacertae objects], distances and redshifts [Galaxies], ta115, 010308 nuclear & particles physics, Gamma rays, Astronomy, Astronomy and Astrophysic, Redshift, Crab Nebula, 13. Climate action, Galàxies actives, Active galaxies, ddc:520
Abstract

The MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes observed the BL Lac object H1722+119 (redshift unknown) for six consecutive nights between 2013 May 17 and 22, for a total of 12.5 h. The observations were triggered by high activity in the optical band measured by the KVA (Kungliga Vetenskapsakademien) telescope. The source was for the first time detected in the very high energy (VHE, $E > 100$ GeV) $\gamma$-ray band with a statistical significance of 5.9 $\sigma$. The integral flux above 150 GeV is estimated to be $(2.0\pm 0.5)$ per cent of the Crab Nebula flux. We used contemporaneous high energy (HE, 100 MeV $ < E < 100$ GeV) $\gamma$-ray observations from Fermi-LAT (Large Area Telescope) to estimate the redshift of the source. Within the framework of the current extragalactic background light models, we estimate the redshift to be $z = 0.34 \pm 0.15$. Additionally, we used contemporaneous X-ray to radio data collected by the instruments on board the Swift satellite, the KVA, and the OVRO (Owens Valley Radio Observatory) telescope to study multifrequency characteristics of the source. We found no significant temporal variability of the flux in the HE and VHE bands. The flux in the optical and radio wavebands, on the other hand, did vary with different patterns. The spectral energy distribution (SED) of H1722+119 shows surprising behaviour in the $\sim 3\times10^{14} - 10^{18}$ Hz frequency range. It can be modelled using an inhomogeneous helical jet synchrotron self-Compton model., Comment: 12 pages, 5 figures, 2 tables

Published
2016
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35. Refining the origins of the gamma-ray binary 1FGL J1018.6–5856

Author

Philip G. Edwards, M. Ribó, J. M. Paredes, Benito Marcote, and Minnie Mao

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Proper motion, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrometry, Compact star, Galactic plane, 01 natural sciences, Galaxy, Radial velocity, Space and Planetary Science, 0103 physical sciences, Peculiar velocity, Astrophysics - High Energy Astrophysical Phenomena, Supernova remnant, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Gamma-ray binaries are systems composed of a massive star and a compact object that exhibit emission from radio to very high energy gamma rays. They are ideal laboratories to study particle acceleration and a variety of physical processes that vary as a function of the orbital phase. We aim to study the radio emission of the gamma-ray binary 1FGL J1018.6-5856 to constrain the emitting region and determine the peculiar motion of the system within the Galaxy to clarify its origin by analyzing an observation with the Australian Long Baseline Array at 8.4~GHz. We combined these data with the optical Gaia DR2 and UCAC4 catalogs to consolidate the astrometry information therein. 1FGL J1018.6-5856 shows compact radio emission ($< 3$ mas or $\lesssim 20$ au at $\sim 6.4$ kpc distance), implying a brightness temperature of $\gtrsim 5.6 \times 10^6$ K, and confirming its nonthermal origin. We report consistent results between the proper motion reported by Gaia DR2 and the positions obtained from the Gaia, UCAC4, and LBA data. We also determined the distance to 1FGL J1018.6-5856 to be $6.4_{-0.7}^{+ 1.7}$ kpc. Together with the radial velocity of the source we computed its three-dimensional proper and peculiar motion within the Galaxy. We obtained a peculiar motion on its regional standard of rest (RSR) frame of $|u| = 45_{-9}^{+30}$ km s$^{-1}$, with the system moving away from the Galactic plane. In the simplest scenario of a symmetric stellar core collapse we estimate a mass loss of $ 4 \lesssim \Delta M \lesssim 9$ M$_{\odot}$ during the creation of the compact object. 1FGL J1018.6-5856 exhibits compact radio emission similar to that detected in other gamma-ray binaries. We provide the first accurate peculiar motion estimations of the system and place it within the Galaxy. The obtained motion and distance excludes its physical relation with the supernova remnant G284.3-1.8., Comment: 8 pages, 7 figures, Accepted for publication by A&A

Published
2018
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36. Observations of Sagittarius A* during the pericenter passage of the G2 object with MAGIC

Author

D. Paneque, D. Garrido Terrats, T. Schweizer, L. Nogués, M. Engelkemeier, M. Makariev, Masahiro Teshima, J. Becerra González, Alessandro Carosi, X. Paredes-Fortuny, F. Di Pierro, A. González Muñoz, A.-K. Overkemping, M. Hayashida, Ruben Lopez-Coto, Elina Lindfors, Laura Maraschi, S. Ansoldi, B. Biasuzzi, Ana Babić, D. Nakajima, J. Rico, M. V. Fonseca, Daniel Mazin, A. Berti, P. Da Vela, Juan Abel Barrio, Jose Miguel Miranda, Arka Chatterjee, Iva Šnidarić, Kyoshi Nishijima, Abelardo Moralejo, A. Treves, Vitaly Neustroev, P. Majumdar, Jose Carlos Herrera, R. J. García López, Benito Marcote, S. Schroeder, T. Steinbring, C. Arcaro, Dariusz Gora, E. Moretti, Pierre Colin, F. Borracci, M. Ribó, Kari Nilsson, K. Frantzen, A. De Angelis, Yusuke Konno, M. Will, Christian Fruck, Stefano Covino, Julian Sitarek, D. Lelas, U. Menzel, I. Puljak, A. Niedzwiecki, Riccardo Paoletti, Julia Thaele, Elisa Prandini, J. Kushida, Dario Hrupec, D. Hadasch, Markus Gaug, D. Galindo, Aaron Dominguez, I. Reichardt, Petar Temnikov, G. Vanzo, R. Zanin, Razmik Mirzoyan, Jose Luis Contreras, Simona Paiano, J. Palacio, M. A. Lopez, Elisa Bernardini, G. Pedaletti, Juan Cortina, A. Biland, Antonio Stamerra, K. Noda, D. Fidalgo, M. Mariotti, J. E. Ward, Juri Poutanen, Dorota Sobczyńska, D. Guberman, Tihomir Surić, Giacomo Bonnoli, J. M. Paredes, S. Bonnefoy, P. Antoranz, G. Maneva, Marina Manganaro, E. de Ona Wilhelmi, M. I. Martínez, W. Idec, P. Bangale, M. Strzys, P. G. Prada Moroni, Diego F. Torres, Konstancja Satalecka, Sabrina Einecke, Michele Doro, A. Sillanpää, K. Kodani, Francesco Longo, V. Fallah Ramazani, Karl Mannheim, Takashi Saito, Max Ludwig Ahnen, Oscar Blanch, M. H. Wu, U. Barres de Almeida, L. Perri, A. La Barbera, Takeshi Toyama, D. Eisenacher Glawion, K. Mallot, M. Nievas Rosillo, J. R. Garcia, Massimo Persic, Leo O. Takalo, Ievgen Vovk, A. Hahn, Hidetoshi Kubo, B. De Lotto, M. Doert, W. Bednarek, V. Verguilov, J. Hose, S. Buson, D. Elsaesser, Markus Garczarczyk, B. Banerjee, Thomas Bretz, S. N. Shore, D. Dominis Prester, S. Lombardi, M. Peresano, Gareth Hughes, Tomislav Terzić, D. Tescaro, N. Godinović, D. Dorner, L. A. Antonelli, R. Clavero, Fabrizio Tavecchio, Eduardo Colombo, Ll. Font, P. Giammaria, M. Palatiello, Francesco Dazzi, A. Fernández-Barral, W. Rhode, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Arcaro, C., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Berti, Alessio, Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Buson, S., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Oña Wilhelmi, E., Di Pierro, F., Doert, M., Domã­nguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Engelkemeier, M., Fallah Ramazani, V., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C, Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinoviä , N., González Muñoz, A., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, Lã³pez, M., López Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martã­nez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Noguã©s, L., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Peresano, M., Perri, L., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribã³, M., Rico, J., Saito, T., Satalecka, K., Schroeder, S., Schweizer, T., Shore, S. N., Sillanpã¤ã¤, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Suriä , T., Takalo, L., Tavecchio, F., Temnikov, P., Terziä , T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Vanzo, G., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., and Zanin, R.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, black hole physics, general [Gamma rays], Galaxy: center, gamma rays: general, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Black hole physic, 0103 physical sciences, MAGIC (telescope), Black hole physics, Gamma rays: general, Astronomy and Astrophysics, Space and Planetary Science, Supernova remnant, 010303 astronomy & astrophysics, Cherenkov radiation, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Galactic Center, center [Galaxy], Astronomy and Astrophysic, Galaxy, Black hole, Sagittarius A, ddc:520, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Astronomy and astrophysics 601, A33 (2017). doi:10.1051/0004-6361/201629355, Context. We present the results of a multi-year monitoring campaign of the Galactic center (GC) with the MAGIC telescopes. These observations were primarily motivated by reports that a putative gas cloud (G2) would be passing in close proximity to the super-massive black hole (SMBH), associated with Sagittarius A*, located at the center of our galaxy. This event was expected to give astronomers a unique chance to study the effect of in-falling matter on the broad-band emission of a SMBH.Aims. We search for potential flaring emission of very-high-energy (VHE; ≥100 GeV) gamma rays from the direction of the SMBH at the GC due to the passage of the G2 object. Using these data we also study the morphology of this complex region.Methods. We observed the GC region with the MAGIC Imaging Atmospheric Cherenkov Telescopes during the period 2012–2015, collecting 67 h of good-quality data. In addition to a search for variability in the flux and spectral shape of the GC gamma-ray source, we use a point-source subtraction technique to remove the known gamma-ray emitters located around the GC in order to reveal the TeV morphology of the extended emission inside that region.Results. No effect of the G2 object on the VHE gamma-ray emission from the GC was detected during the 4 yr observation campaign. We confirm previous measurements of the VHE spectrum of Sagittarius A*, and do not detect any significant variability of the emission from the source. Furthermore, the known VHE gamma-ray emitter at the location of the supernova remnant G0.9+0.1 was detected, as well as the recently discovered VHE source close to the GG radio arc.Key words: Galaxy: center / gamma rays: general / black hole physics, Published by EDP Sciences, Les Ulis

Published
2016
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37. Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009

Author

K. Nishijima, J. L. Richards, Stefano Covino, G. Piner, D. Dominis Prester, U. Menzel, A. Flinders, D. Tescaro, Louis Antonelli, D. Galindo, Aaron Dominguez, S. Schröder, Elena G. Larionova, Kari Nilsson, Paul S. Smith, A. McCann, T. S. Grishina, Wen Ping Chen, M. Will, Pratik Majumdar, J. E. Ward, Daniela Dorner, Dariusz Gora, P. Moriarty, C. Rulten, Soebur Razzaque, D. Garrido Terrats, K. Frantzen, Joseph Moody, Wystan Benbow, G. Hughes, K. Ragan, Ralph Bird, L. Perri, M. Gaug, T. Sakamoto, Valeri M. Larionov, Elina Lindfors, G. H. Sembroski, Daniel Mazin, Ievgen Vovk, A. Hahn, M. Hütten, N. H. Park, Alexander B. Pushkarev, G. Maccaferri, Thomas Bretz, P. Wilcox, P. Kar, D. Nakajima, R. Zanin, J. Herrera, Wei Cui, Amanda Weinstein, J. Palacio, P. G. Prada Moroni, Frank Krennrich, Matthew L. Lister, A. Berti, A. Cesarini, M. Kertzman, A. La Barbera, Walter Max-Moerbeck, E. Colombo, M. Villata, M. P. Connolly, Adrian Biland, D. S. Hanna, Ana Babić, D. Eisenacher Glawion, Juan Abel Barrio, John L. Quinn, M. Capalbi, Koji Noda, Arka Chatterjee, Elisa Bernardini, A. Sillanpää, Adrian Rovero, Antonio Stamerra, J. V. Tucci, M. Nievas Rosillo, M. Palatiello, L. V. Larionova, S. N. Shore, R. Mukherjee, M. J. Lang, Daniel Nieto, M. I. Martínez, S. Bonnefoy, J. Kushida, P. Giammaria, P. Bangale, Wolfgang Rhode, Gernot Maier, G. Pedaletti, L. O. Takalo, Margo F. Aller, Jose Luis Contreras, Andrei Berdyugin, J. A. Zensus, E. Roache, V. Verguilov, D. Fidalgo, C. Pace, Thomas P. Krichbaum, Francesco Dazzi, Juan Cortina, M. Engelkemeier, G. H. Gillanders, A. Carraminyana, S. P. Wakely, Mosè Mariotti, J. Rico, A. Fernández-Barral, R. Clavero, J. Becerra González, A.-K. Overkemping, S. O. Kurtanidze, Sabrina Einecke, Abraham D. Falcone, A. González Muñoz, Evgenia N. Kopatskaya, Lars Fuhrmann, Nikola Godinovic, Benito Marcote, Karlen Shahinyan, Takashi Saito, W. Bednarek, C. Schultz, Marcos Santander, Fabrizio Tavecchio, J. Rodriguez Garcia, E. Pueschel, Ll. Font, A. C. Sadun, A. Popkow, J. Grube, V. Bugaev, Anthony C. S. Readhead, R. Ligustri, A. Archer, I. Snidaric, Yusuke Konno, P. Calcidese, M. Strzys, A. Pichel, Saverio Lombardi, B. De Lotto, Markus Garczarczyk, N. Kelley-Hoskins, J. Tyler, Ann E. Wehrle, B. Banerjee, S. Buson, D. Hadasch, N. Otte, Maria G. Nikolashvili, Gordon T. Richards, L. Nogués, B. Biasuzzi, Juri Poutanen, U. Barres de Almeida, J. P. Finley, K. Mallot, S. Paiano, Marcello Giroletti, I. Nestoras, A. De Angelis, A. Treves, Vitaly Neustroev, X. Paredes-Fortuny, T. B. Humensky, R. A. Ong, Karl Mannheim, J. H. Buckley, Yu. A. Kovalev, R. J. García López, H. Fleischhack, G. N. Kimeridze, I. Sadeh, David A. Williams, Y. Mori, M. V. Fonseca, W. Idec, Matthias Kadler, Yuri Y. Kovalev, Stefano Ansoldi, Riccardo Paoletti, K. Kodani, J. P. Norris, O. M. Kurtanidze, N. V. Efimova, Y. Hanabata, Arkady A. Arkharov, Anne Lähteenmäki, Abelardo Moralejo, G. Maneva, Masahiro Teshima, A. C. Zook, Dario Hrupec, P. Antoranz, B. Zitzer, Hugh Dickinson, R. A. Chigladze, M. Peresano, Ekaterina Koptelova, S. Archambault, M. A. Lopez, T. Steinbring, P. Temnikov, P. Leto, Massimo Persic, J. M. Paredes, Hugh D. Aller, F. Borracci, S. O'Brien, T. Surić, I. Telezhinsky, I. Reichardt, Jamie Holder, G. Vanzo, R. Pearson, Julia Thaele, G. Bonnoli, Mark Gurwell, Eduardo Ros, Andrea Orlati, S. Griffin, L. A. Sigua, Diego F. Torres, Alessandro Carosi, Ruben Lopez-Coto, Maria Krause, Y. Yatsu, A. Wilhelm, Jose Miguel Miranda, Anushka Udara Abeysekara, T. Schweizer, P. Cassaro, Razmik Mirzoyan, E. Moretti, Damir Lelas, Francesco Longo, V. Fallah Ramazani, P. Kaaret, Dorota Sobczyńska, L. Maraschi, Kirill Sokolovsky, Tomislav Terzić, Lucy Fortson, E. de Ona Wilhelmi, Julian Sitarek, C. Fruck, T. Toyama, Ivica Puljak, Max Ludwig Ahnen, David Kieda, F. Di Pierro, Pierre Colin, M. Buchovecky, Oscar Blanch, P. Da Vela, A. Niedzwiecki, Emmanouil Angelakis, M. Doert, M. H. Wu, Ivan S. Troitsky, C. Pagani, David Paneque, Q. Feng, Vladimir A. Hagen-Thorn, E. De la Fuente, E. Prandini, C. M. Raiteri, L. Carrasco, D. Guberman, Jeremy S. Perkins, Martin Pohl, Marina Manganaro, H. A. Krimm, Merja Tornikoski, Konstancja Satalecka, Michele Doro, Dmitry A. Blinov, M. Perri, J. Hose, D. Elsaesser, Daria A. Morozova, P. T. Reynolds, M. Hayashida, Marc Ribó, Hidetoshi Kubo, M. Makariev, Swiss Federal Institute of Technology Zurich, University of Udine, INAF National Institute for Astrophysics, University of Siena, University of Rijeka, Saha Institute of Nuclear Physics, Max Planck Institute for Physics, Complutense University, University of La Laguna, University of Łódź, German Electron Synchrotron, Autonomous University of Barcelona, University of Würzburg, University of Padova, Institute of Space Studies of Catalonia, Dortmund University, Finnish MAGIC Consortium, University of Barcelona, The University of Tokyo, Bulgarian Academy of Sciences, Osservatorio Astronomicodi Roma, University of Pisa, ICREA, University of Maryland, College Park, McGill University, Washington University St. Louis, Harvard University, University College Dublin, University of California Los Angeles, National University of Ireland, Galway, Purdue University, Iowa State University, Pennsylvania State University, University of Utah, University of Minnesota Twin Cities, Adler Planetarium and Astronomy Museum, University of Delaware, Columbia University, University of Iowa, DePauw University, Georgia Institute of Technology, University of Chicago, NASA Goddard Space Flight Center, Universidad de Buenos Aires, Cork Institute of Technology, University of California Santa Cruz, Argonne National Laboratory, University of Johannesburg, University of Michigan, Ann Arbor, St. Petersburg State University, RAS - Pulkovo Astronomical Observatory, Circolo Astrofili Talmassons, Osservatorio Astrofisico della Regione Autonoma Valle d'Aosta, Georgian National Academy of Sciences, National Central University, Aoyama Gakuin University, University of Colorado Denver, Brigham Young University, Tokyo Institute of Technology, Instituto Nacional de Astrofisica Optica y Electronica, Universidad de Guadalajara, University of Denver, University of Arizona, Space Science Institute, Pomona College, University of Leicester, ASI Science Data Center, University of Trento, RAS - P.N. Lebedev Physics Institute, Max Planck Institute for Radio Astronomy, Whittier College, Metsähovi Radio Observatory, INAF Istituto di Radioastronomia, Osservatorio Astrofisico di Catania, California Institute of Technology, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Berti, Alessio, Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Buson, S., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Oña Wilhelmi, E., Di Pierro, F., Doert, M., Domã­nguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Engelkemeier, M., Fallah Ramazani, V., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinoviä , N., González Muñoz, A., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, Lã³pez, M., López Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martã­nez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Noguã©s, L., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Peresano, M., Perri, L., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reichardt, I., Rhode, W., Ribã³, M., Rico, J., Rodriguez Garcia, J., Saito, T., Satalecka, K., Schrã¶der, S., Schultz, C., Schweizer, T., Shore, S. N., Sillanpã¤ã¤, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Suriä , T., Takalo, L., Tavecchio, F., Temnikov, P., Terziä , T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Vanzo, G., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Abeysekara, A. U., Archambault, S., Archer, A., Benbow, W., Bird, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Connolly, M. P., Cui, W., Dickinson, H. J., Falcone, A., Feng, Q., Finley, J. P., Fleischhack, H., Flinders, A., Fortson, L., Gillanders, G. H., Griffin, S., Grube, J., Hã¼tten, M., Hanna, D., Holder, J., Humensky, T. B., Kaaret, P., Kar, P., Kelley Hoskins, N., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Lang, M. J., Maier, G., Mccann, A., Moriarty, P., Mukherjee, R., Nieto, D., O'Brien, S., Ong, R. A., Otte, N., Park, N., Perkins, J., Pichel, A., Pohl, M., Popkow, A., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rovero, A. C., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Telezhinsky, I., Tucci, J. V., Tyler, J., Wakely, S. P., Weinstein, A., Wilcox, P., Wilhelm, A., Williams, D. A., Zitzer, B., Razzaque, S., Villata, M., Raiteri, C. M., Aller, H. D., Aller, M. F., Larionov, V. M., Arkharov, A. A., Blinov, D. A., Efimova, N. V., Grishina, T. S., Hagen Thorn, V. A., Kopatskaya, E. N., Larionova, L. V., Larionova, E. G., Morozova, D. A., Troitsky, I. S., Ligustri, R., Calcidese, P., Berdyugin, A., Kurtanidze, O. M., Nikolashvili, M. G., Kimeridze, G. N., Sigua, L. A., Kurtanidze, S. O., Chigladze, R. A., Chen, W. P., Koptelova, E., Sakamoto, T., Sadun, A. C., Moody, J. W., Pace, C., Pearson, R., Yatsu, Y., Mori, Y., Carraminyana, A., Carrasco, L., De La Fuente, E., Norris, J. P., Smith, P. S., Wehrle, A., Gurwell, M. A., Zook, A., Pagani, C., Perri, M., Capalbi, M., Cesarini, A., Krimm, H. A., Kovalev, Y. Y., Kovalev, Y. u. A., Ros, E., Pushkarev, A. B., Lister, M. L., Sokolovsky, K. V., Kadler, M., Piner, G., Lã¤hteenmã¤ki, A., Tornikoski, M., Angelakis, E., Krichbaum, T. P., Nestoras, I., Fuhrmann, L., Zensus, J. A., Cassaro, P., Orlati, A., Maccaferri, G., Leto, P., Giroletti, M., Richards, J. L., Max Moerbeck, W., and Readhead, A. C. S.

Subjects
extragalactic background light, multiwavelength observations, Astrophysics::High Energy Astrophysical Phenomena, bl-lacertae objects, Galaxies: BL Lacertae objects: individual: Markarian 501, Methods: data analysis, observational, Polarization, spectral energy-distribution, Flux, FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, individual: Markarian 501 [BL Lacertae objects], law, Coincident, 0103 physical sciences, ddc:530, MAGIC (telescope), crab-nebula, Blazar, data analysis [Methods], 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), tev blazars, 010308 nuclear & particles physics, stochastic acceleration, telescope observations, Institut für Physik und Astronomie, Astronomy and Astrophysics, Astronomy and Astrophysic, gamma-ray emission, methods: data analysis, BL Lacertae objects: individual: Markarian 501, Synchrotron, data analysi [Methods], Space and Planetary Science, x-ray, ddc:520, Electrónica, Física nuclear, Electricidad, Degeneracy (mathematics), Astrophysics - High Energy Astrophysical Phenomena, Flare, BL Lac object
Abstract

Astronomy and astrophysics 603, A31 (2017). doi:10.1051/0004-6361/201629540, We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi-LAT to cover the γ-ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV tohard X-rays; and GASP-WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the γ-ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self-Compton (SSC) scenarios. Aims. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters, hence providing a less biased interpretation than the “single-curve SSC model adjustment” typically reported in the literature. Methods. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid-scan shows that the flaring activity around May 22 cannot be modeled adequately with a one-zone SSC scenario (using an electron energy distribution with two breaks), while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5-month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X-rays and very-high-energy (>100 GeV, VHE) γ rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA), cannot be satisfactorily reproduced by either a one-zone or a two-independent-zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub-hour timescales (detected at VHE γ rays). Results. The higher variability in the VHE emission and lack of correlation with the X-ray emission indicate that, at least during the 4.5-month observing campaign in 2009, the highest energy (and most variable) electrons that are responsible for the VHE γ rays do not make a dominant contribution to the ~1 keV emission. Alternatively, there could be a very variable component contributing to the VHE γ-ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid-scan show that there is some degeneracy in both the one-zone and the two-zone SSC scenarios probed, with several combinations of model parameters yielding a similar model-to-data agreement, and some parameters better constrained than others. The observed γ-ray flaring activity, with the EVPA rotation coincident with the first γ-ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties., Published by EDP Sciences, Les Ulis

Published
2016
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38. MAGIC observations of the February 2014 flare of 1ES 1011+496 and ensuing constraint of the EBL density

Author

Dominik Elsaesser, U. Barres de Almeida, Damir Lelas, A. Stamerra, L. A. Antonelli, Dorota Sobczyńska, Max Ludwig Ahnen, E. Moretti, B. Biasuzzi, Abelardo Moralejo, Thomas Bretz, R. Paoletti, J. M. Mira, T. Steinbring, J. Becerra González, Marcel Strzys, Julian Sitarek, J. Hose, K. Nishijima, T. Toyama, J. Rico, Wolfgang Rhode, Martin Makariev, P. Giammaria, Aldo Treves, Oscar Blanch, A. Carosi, Christian Fruck, S. Bonnefoy, D. Garrido Terrats, Eckart Lorenz, A. La Barbera, M. H. Wu, Nikola Godinovic, Marina Manganaro, Ivica Puljak, Benito Marcote, A. Bil, B. De Lotto, D. Nakajima, Pratik Majumdar, X. Paredes-Fortuny, A. De Angelis, M. V. Fonseca, M. Nievas Rosillo, B. Banerjee, R. Mirzoyan, Miriam Lucio Martinez, Vitaly Neustroev, S. N. Shore, D. Galindo, K. Frantzen, Martin Will, Arka Chatterjee, E. Lindfors, A. Sillanpää, E. de Oña Wilhelmi, K. Nilsson, D. Eisenacher Glawion, Fabrizio Tavecchio, D. Fidalgo, Roberta Zanin, U. Menzel, G. Maneva, Stefano Ansoldi, Ll. Font, S. Paiano, M. Lopez, E. Carmona, Karl Mannheim, K. Kodani, F. Borracci, I. Snidaric, Alicia López-Oramas, Juan Abel Barrio, K. Mallot, R. J. García López, Diego F. Torres, Reiko Orito, J. M. Paredes, M. Garczarczyk, H. Takami, Yusuke Konno, J. Palacio, Vassil Verguilov, Massimo Persic, Konstancja Satalecka, Dario Hrupec, J. E. Ward, Julia Thaele, L. Maraschi, Michele Doro, Giacomo Bonnoli, M. Hayashida, Ana Babić, P. G. Prada Moroni, P. Temnikov, Daniel Mazin, F. Longo, Sabrina Einecke, J. Rodriguez Garcia, Marc Ribó, Wlodek Bednarek, Tomislav Terzić, P. Bangale, R. López-Coto, A. Niedzwiecki, Hidetoshi Kubo, Francesco Dazzi, Ievgen Vovk, C. Delgado Mendez, T. Schweizer, David Paneque, Stefano Covino, Juri Poutanen, Y. Hanabata, D. Guberman, P. Antoranz, Masahiro Teshima, Michele Palatiello, Jose Luis Contreras, Tomoki Saito, D. Tescaro, Juan Cortina, G. Hughes, Daniela Dorner, Alexander Hahn, M. Gaug, D. Dominis Prester, R. Clavero, E. Prini, J. Herrera, Koji Noda, Elisa Bernardini, E. Colombo, P. Colin, A. González Muñoz, L. O. Takalo, C. Schultz, F. Di Pierro, Junko Kushida, P. Da Vela, Alba Fernández-Barral, W. Idec, Mosè Mariotti, A.-K. Overkemping, Saverio Lombardi, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P, Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Ona Wilhelmi, E., Delgado Mendez, C., Di Pierro, F., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Fernandez Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., Garcia Lopez, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinovic, N., Gonzalez Munoz, A., Guberman, D., Hahn, A., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, Lopez, M., Lopez Coto, R., Lopez Oramas, A., Lorenz, E., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martinez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Rodriguez Garcia, J., Saito, T., Satalecka, K., Schultz, C., Schweizer, T., Shore, S. N., Sillanpaa, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., and Universitat de Barcelona

Subjects
Flux, DIRBE, Astrophysics, cosmic background radiation, Cosmic background radiation, 01 natural sciences, Spectral line, law.invention, 3.5 MU-M, law, Optical depth (astrophysics), NUMBER COUNTS, 010303 astronomy & astrophysics, MINUS 2MASS, SPITZER-SPACE-TELESCOPE, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), TEV BLAZARS, Cosmology, Extragalactic background light, ENERGY GAMMA-RAYS, Electrónica, Física nuclear, intergalactic medium, cosmic background, MICRON SOURCE COUNTS, Electricidad, BL Lacertae objects, general, Astrophysics - High Energy Astrophysical Phenomena, Flare, Astrophysics - Cosmology and Nongalactic Astrophysics, BL Lacertae objects: general, Intergalactic medium, Astronomy and Astrophysics, Space and Planetary Science, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Opacity, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, GALAXY COUNTS, 0103 physical sciences, TELESCOPE IMAGING SPECTROGRAPH, Cosmologia, 010308 nuclear & particles physics, general [BL Lacertae objects], Astronomy and Astrophysic, Light curve, radiation, EXTRAGALACTIC BACKGROUND LIGHT, Likelihood-ratio test, ddc:520
Abstract

Astronomy and astrophysics 590, A24(2016). doi:10.1051/0004-6361/201527256, During February–March 2014, the MAGIC telescopes observed the high-frequency peaked BL Lac 1ES 1011+496 (z = 0.212) in flaring state at very-high energy (VHE, E> 100 GeV). The flux reached a level of more than ten times higher than any previously recorded flaring state of the source.Aims. To describe the characteristics of the flare presenting the light curve and the spectral parameters of the night-wise spectra and the average spectrum of the whole period. From these data we aim to detect the imprint of the extragalactic background light (EBL) in the VHE spectrum of the source, to constrain its intensity in the optical band.Methods. We analyzed the gamma-ray data from the MAGIC telescopes using the standard MAGIC software for the production of the light curve and the spectra. To constrain the EBL, we implement the method developed by the H.E.S.S. collaboration, in which the intrinsic energy spectrum of the source is modeled with a simple function (≤4 parameters), and the EBL-induced optical depth is calculated using a template EBL model. The likelihood of the observed spectrum is then maximized, including a normalization factor for the EBL opacity among the free parameters.Results. The collected data allowed us to describe the night-wise flux changes and also to produce differential energy spectra for all nights in the observed period. The estimated intrinsic spectra of all the nights could be fitted by power-law functions. Evaluating the changes in the fit parameters, we conclude that the spectral shape for most of the nights were compatible, regardless of the flux level, which enabled us to produce an average spectrum from which the EBL imprint could be constrained. The likelihood ratio test shows that the model with an EBL density 1.07 (–0.20, +0.24)$_{stat+sys}$, relative to the one in the tested EBL template, is preferred at the 4.6σ level to the no-EBL hypothesis, with the assumption that the intrinsic source spectrum can be modeled as a log-parabola. This would translate into a constraint of the EBL density in the wavelength range [0.24 μm, 4.25 μm], with a peak value at 1.4 μm of λF$_λ$ = 12.27$_{-2.29}^{+2.75}$ nW m$^{-2}$ sr$^{-1}$, including systematics., Published by EDP Sciences, Les Ulis

Published
2016
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39. Super-orbital variability of LS I +61 ° 303 at TeV energies

Author

E. Colombo, K. Mallot, R. J. García López, M. H. Wu, D. Nakajima, L. O. Takalo, H. Takami, Arka Chatterjee, Christian Fruck, Sabrina Einecke, Vassil Verguilov, D. Fidalgo, Ivica Puljak, Pierre Colin, J. Rodriguez Garcia, Daniela Dorner, Dariusz Gora, Massimo Persic, E. de Oña Wilhelmi, Masahiro Teshima, Alexander Hahn, J. Palacio, M. Palatiello, J. M. Paredes, Antonio Stamerra, Francesco Longo, Gareth Hughes, M. Gaug, I. Snidaric, Yusuke Konno, J. Herrera, Stefano Ansoldi, Pratik Majumdar, M. V. Fonseca, A. La Barbera, Lluis Font, Riccardo Paoletti, Julian Sitarek, K. Kodani, Koji Noda, J. Hose, Elisa Bernardini, Francesco Dazzi, Marcel Strzys, D. Dominis Prester, D. Eisenacher Glawion, X. Paredes-Fortuny, M. Nievas Rosillo, A. Herrero, E. Moretti, Nikola Godinovic, Stefano Covino, P. Temnikov, Martin Makariev, Benito Marcote, Oscar Blanch, T. Toyama, G. Pedaletti, Dominik Elsaesser, S. Bonnefoy, Jose Luis Contreras, U. Barres de Almeida, Damir Lelas, Juan Cortina, D. Garrido Terrats, U. Menzel, Diego F. Torres, M. Garczarczyk, F. Di Pierro, Juan Abel Barrio, J. E. Ward, Giacomo Bonnoli, P. G. Prada Moroni, K. Frantzen, S. Paiano, R. López-Coto, A. Niedzwiecki, David Paneque, D. Guberman, Marina Manganaro, M. Hayashida, Thomas Bretz, S. N. Shore, R. Mirzoyan, Tomoki Saito, D. Tescaro, Jorge Casares, Mosè Mariotti, A.-K. Overkemping, A. González Muñoz, Kyoshi Nishijima, Dorota Sobczyńska, E. Prandini, Tomislav Terzić, Marc Ribó, B. De Lotto, C. Schultz, Aaron Dominguez, Karl Mannheim, Alicia López-Oramas, D. Galindo, Saverio Lombardi, P. Bangale, Hidetoshi Kubo, S. Buson, Junko Kushida, P. Da Vela, J. Becerra González, Wolfgang Rhode, D. Hadasch, Max Ludwig Ahnen, C. Delgado Mendez, Reiko Orito, Ana Babić, Konstancja Satalecka, Alba Fernández-Barral, F. Borracci, L. Maraschi, Michele Doro, Elina Lindfors, Dario Hrupec, B. Biasuzzi, Daniel Mazin, M. A. Lopez, Kari Nilsson, A. Sillanpää, M. Will, W. Idec, Abelardo Moralejo, P. Giammaria, T. Steinbring, Wlodek Bednarek, Alessandro Carosi, L. A. Antonelli, B. Banerjee, R. Clavero, Miriam Lucio Martinez, Fabrizio Tavecchio, Jose Miguel Miranda, A. De Angelis, A. Treves, Vitaly Neustroev, Ievgen Vovk, G. Maneva, R. Zanin, Adrian Biland, T. Schweizer, J. Rico, Julia Thaele, Juri Poutanen, Y. Hanabata, P. Antoranz, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Buson, S., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Oña Wilhelmi, E., Delgado Mendez, C., Di Pierro, F., Domínguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinović, N., González Muñoz, A., Gora, D., Guberman, D., Hadasch, D, Hahn, A., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., López Oramas, A., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Saito, T., Satalecka, K., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Casares, J., Herrero, A., and Universitat de Barcelona

Subjects
Astrofísica, astroparticle physics, binaries: general, gamma rays: general, stars: individual: LS I +61°303, X-rays: binaries, X-rays: individuals: LS I +61°303, Be star, Astrophysics::High Energy Astrophysical Phenomena, Gamma rays: general, general [Gamma rays], Binary number, FOS: Physical sciences, Astrophysics, 01 natural sciences, Astroparticle physic, Radio spectrum, law.invention, individual: LS I +61°303 [Stars], Telescope, Raigs gamma, law, 0103 physical sciences, Modulation (music), individuals: LS I +61°303 [X-rays], Astroparticle physics, Binaries: general, Stars: individual: LS I +61°303, Astronomy and Astrophysics, Space and Planetary Science, MAGIC (telescope), Spectroscopy, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), general [Binaries], 010308 nuclear & particles physics, binarie [X-rays], Gamma rays, Astronomy and Astrophysic, Orbital period, ddc:520, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Astronomy and astrophysics 591, A76(2016). doi:10.1051/0004-6361/201527964, The gamma-ray binary LS I +61°303 is a well-established source from centimeter radio up to very high energy (VHE;E > 100 GeV).The broadband emission shows a periodicity of $\sim$ 26.5 days, coincident with the orbital period. A longer (super-orbital) period of 1667 $\pm$ 8 dayswas proposed from radio variability and confirmed using optical and high-energy (HE; E > 100 MeV) gamma-ray observations. In this paper, wereport on a four-year campaign performed by MAGIC together with archival data concentrating on a search for a long-timescale signature in the VHE emission from LS I +61°303 Aims.We focus on the search for super-orbital modulation of the VHE emission, similar to that observed at other energies, and on the search forcorrelations between TeV emission and an optical determination of the extension of the circumstellar disk.Methods. A four-year campaign has been carried out using the MAGIC telescopes. The source was observed during the orbital phases when theperiodic VHE outbursts have occurred ($\phi$ = 0:55–0.75, one orbit=26.496 days). Additionally, we included archival MAGIC observations anddata published by the VERITAS collaboration in these studies. For the correlation studies, LS I +61°303 has also been observed during the orbitalphases where sporadic VHE emission had been detected in the past ($\phi$ = 0:75–1.0). These MAGIC observations were simultaneous with opticalspectroscopy from the LIVERPOOL telescope.Results.The TeV flux of the periodical outburst in orbital phases $\phi$ = 0:5–0.75 was found to show yearly variability consistent with the long-term modulation of$\sim$ 4.5 years found in the radio band. This modulation of the TeV flux can be well described by a sine function with a best-fit period of 1610 $\pm$ 58 days. The complete data, including archival observations, span two super-orbital periods. There is no evidence for a correlation betweenthe TeV emission and the mass-loss rate of the Be star, but this may be a ected by the strong, short-timescale (as short as intra-day) variation displayed by the Hfluxes., Published by EDP Sciences, Les Ulis

Published
2016
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40. The major upgrade of the MAGIC telescopes, Part I: The hardware improvements and the commissioning of the system

Author

R. Zanin, Adrian Biland, I. Lozano, J. Rico, Masahiro Teshima, W. Idec, Takashi Saito, J. Krause, B. De Lotto, Nikola Godinovic, Benito Marcote, Stefano Ansoldi, I. Snidaric, David Fink, K. Mallot, R. J. García López, D. Corti, Alessandro Carosi, Mosè Mariotti, A.-K. Overkemping, J. M. Illa, Riccardo Paoletti, Massimo Persic, Gianluca Giavitto, A. González Muñoz, Reiko Orito, P. Temnikov, M. Palatiello, J. Becerra González, Marcel Strzys, Dario Hrupec, M. Bitossi, Ruben Lopez-Coto, Jose Luis Lemus, D. Nakajima, Elina Lindfors, E. Lorenz, Abelardo Moralejo, Saverio Lombardi, A. Treves, Vitaly Neustroev, M. Makariev, Thomas Bretz, Daniel Mazin, Jose Miguel Miranda, M. A. Lopez, S. Rügamer, Juan Abel Barrio, S. Schmidl, T. Steinbring, Francesco Dazzi, J. M. Paredes, Antonio Stamerra, C. Delgado Mendez, G. Maneva, Stefano Covino, B. Biasuzzi, A. Dettlaff, M. Hayashida, D. Hildebrand, Francesco Longo, G. De Caneva, D. Fidalgo, Daniela Dorner, Jose Luis Contreras, Wolfgang Rhode, M. I. Martínez, Marc Ribó, S. Bonnefoy, K. Saito, Natalia Lewandowska, Patrick Vogler, E. Colombo, M. Gaug, Juan Cortina, D. Tescaro, Roberto Cecchi, P. Bangale, H. Wetteskind, A. La Barbera, A. Deangelis, J. Herrera, Hidetoshi Kubo, Sabrina Einecke, S. R. Gozzini, Luis Ángel Tejedor, M. V. Fonseca, Hanna Kellermann, Koji Noda, Louis Antonelli, G. Bonnoli, J. Rodriguez Garcia, Elisa Bernardini, X. Paredes-Fortuny, J. Hose, U. Menzel, K. Kodani, J. Storz, Yusuke Konno, Christian Fruck, A. Sillanpää, D. Elsaesser, L. O. Takalo, F. Borracci, W. Haberer, H. Takami, Oscar Blanch, K. Frantzen, P. G. Prada Moroni, Diego F. Torres, W. Bednarek, Fabrizio Tavecchio, V. Kadenius, S. Paiano, Ll. Font, D. Garrido Terrats, A. Lorca, Karl Mannheim, O. Tibolla, Alicia López-Oramas, T. Schweizer, Felix Spanier, R. Mirzoyan, P. Munar-Adrover, D. Eisenacher, V. Scalzotto, Markus Garczarczyk, N. Mankuzhiyil, Juri Poutanen, Kyoshi Nishijima, D. Dominis Prester, Y. Hanabata, C. Schultz, V. Scapin, P. Antoranz, M. L. Knoetig, Ana Babić, Julia Thaele, E. Carmona, Kari Nilsson, M. Will, L. Maraschi, E. Prandini, Tomislav Terzić, R. Reinthal, M. Negrello, Damir Lelas, Dorota Sobczyńska, Ivica Puljak, Pierre Colin, E. de Oña Wilhelmi, Jelena Aleksić, A. Niedzwiecki, David Paneque, M. Barcelo, D. Galindo, Konstancja Satalecka, Michele Doro, Julian Sitarek, Daniela Hadasch, T. Toyama, Junko Kushida, P. Da Vela, J. Schlammer, Universitat de Barcelona, Aleksić, J, Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barceló, M., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Bitossi, M., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Cecchi, R., Colin, P., Colombo, E., Contreras, J. L., Corti, D., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., Deangelis, A., De Caneva, G., De Lotto, B., De Oña Wilhelmi, E., Delgado Mendez, C., Dettlaff, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fidalgo, D., Fink, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giavitto, G., Godinović, N., González Muñoz, A., Gozzini, S. R., Haberer, W., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Illa, J. M., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lemus, J. L., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., López Oramas, A., Lorca, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar Adrover, P., Nakajima, D., Negrello, M., Neustroev, V., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Rügamer, S., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schlammer, J., Schmidl, S., Schweizer, T., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Tejedor, L. A., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Wetteskind, H., Will, M., and Zanin, R.

Subjects
Astrofísica, Physics::Instrumentation and Detectors, MAGIC, Imaging Atmospheric Cherenkov Telescopes, Instruments, TeV astrophysics, Very High Energy Gamma Rays, Stereoscopy, Astrophysics, 01 natural sciences, law.invention, Raigs gamma, law, Overall performance, MAGIC (telescope), TeV, astrophysics, CRAB-NEBULA, PERFORMANCE, STEREO, 010303 astronomy & astrophysics, Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Instrument, Upgrade, ddc:540, Electrónica, Física nuclear, Astrophysics::Earth and Planetary Astrophysics, Electricidad, Astrophysics - Instrumentation and Methods for Astrophysics, TeV astrophysic, Noise (radio), Computer hardware, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Telescope, 0103 physical sciences, Very High Energy Gamma Ray, Instrumentation and Methods for Astrophysics (astro-ph.IM), Cherenkov radiation, ta115, Telescopis, 010308 nuclear & particles physics, business.industry, Gamma rays, Cherenkov Telescope Array, Imaging Atmospheric Cherenkov Telescope, business, astro-ph.IM, Telescopes
Abstract

The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs) located on the Canary island of La Palma. The telescopes are designed to measure Cherenkov light from air showers initiated by gamma rays in the energy regime from around 50 GeV to more than 50 TeV. The two telescopes were built in 2004 and 2009, respectively, with different cameras, triggers and readout systems. In the years 2011-2012 the MAGIC collaboration undertook a major upgrade to make the stereoscopic system uniform, improving its overall performance and easing its maintenance. In particular, the camera, the receivers and the trigger of the first telescope were replaced and the readout of the two telescopes was upgraded. This paper (Part I) describes the details of the upgrade as well as the basic performance parameters of MAGIC such as raw data treatment, dead time of the system, linearity in the electronic chain and sources of noise. In Part II, we describe the physics performance of the upgraded system., 19 pages, 18 figures, accepted by Astroparticle Physics

Published
2016
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41. Non-thermal emission from high-energy binaries through interferometric radio observations

Author

Benito Marcote

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

High-mass binary systems involve extreme environments that produce non-thermal emission from radio to gamma rays. Only three types of these systems are known to emit persistent gamma-ray emission: colliding-wind binaries, high-mass X-ray binaries and gamma-ray binaries. This thesis is focused on the radio emission of high-mass binary systems through interferometric observations, and we have explored several of these sources with low- and high-frequency radio observations, and very high-resolution VLBI ones. We have studied two gamma-ray binaries, LS 5039 and LS I +61 303, at low frequencies. We have obtained their light-curves and spectra, and we have determined the physical properties of their radio emitting regions. We have also studied the gamma-ray binary HESS J0632+057 through VLBI observations. A new colliding wind binary, HD 93129A, has been discovered through VLBI and optical observations. Finally, we have conducted radio observations of two sources that were candidates to be gamma-ray binaries., Comment: 211 pages, PhD Thesis, Universitat de Barcelona

Published
2016
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42. FRB 150418: clues to its nature from European VLBI Network and e-MERLIN observations

Author

Marcello Giroletti, Z. Paragi, M. A. Garrett, Kazuhiro Hada, C. C. Cheung, T. W. B. Muxlow, Benito Marcote, Jun Yang, ITA, USA, GBR, JPN, and NLD

Subjects
Physics, European VLBI Network, Null (radio), 010308 nuclear & particles physics, Epoch (astronomy), Fast radio burst, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Galaxy, Space and Planetary Science, Brightness temperature, 0103 physical sciences, 010303 astronomy & astrophysics, MERLIN
Abstract

Aims: We investigate the nature of the compact and possibly variable nuclear radio source in the centre of WISE J0716-19, the proposed host galaxy of the fast radio burst FRB 150418. Methods: We observed WISE J0716-19 at 5.0 GHz with the European VLBI Network (EVN) four times between 2016 March 16 and June 2. At three epochs, we simultaneously observed the source with e-MERLIN at the same frequency. Results: We detected a compact source in the EVN data in each epoch with a significance of up to ~8σ. The four epochs yielded consistent results within their uncertainties for the peak surface intensity and positions. The mean values for these quantities are Ipeak = (115 ± 9)μJy beam-1 and RA = 07h16m34.55496(7)s, Dec = -19°00'39.4754(8)''. The e-MERLIN data provided ~3-5σ detections at a position consistent with those of the EVN data. The emission on angular scales intermediate between the EVN and e-MERLIN is consistent with being null. The brightness temperature of the EVN core is Tb ≳ 108.5 K, close to the value previously required to explain the short-term radio variability properties of WISE J0716-19 in terms of interstellar scintillation. Conclusions: Our observations provide direct and independent evidence of a nuclear compact source in WISE J0716-19, a physical scenario without evident connection with FRB 150418. However, the EVN data do not indicate the variability observed with the VLA.

Published
2016

43. Long-term multi-wavelength variability and correlation study of Markarian 421 from 2007 to 2009

Author

E. Moretti, Alessandro Carosi, D. Nakajima, Kyoshi Nishijima, Arka Chatterjee, C. M. Raiteri, Nikola Godinovic, Benito Marcote, D. Fidalgo, Jose Miguel Miranda, D. Dominis Prester, Yusuke Konno, B. Jordan, Aaron Dominguez, L. Perri, Elena G. Larionova, Marina Manganaro, Kari Nilsson, Pratik Majumdar, M. V. Fonseca, Wen Ping Chen, M. Will, A. La Barbera, D. Galindo, R. Zanin, Merja Tornikoski, Mosè Mariotti, Dario Hrupec, K. Kodani, S. N. Shore, Louis Antonelli, D. Eisenacher Glawion, Max Ludwig Ahnen, X. Paredes-Fortuny, M. Nievas Rosillo, J. E. Ward, A. González Muñoz, Adrian Biland, A.-K. Overkemping, Razmik Mirzoyan, U. Barres de Almeida, J. Palacio, Dmitry A. Blinov, G. Pedaletti, M. A. Lopez, Juri Poutanen, Konstancja Satalecka, Sofia O. Kurtanidze, Michele Doro, U. Menzel, J. M. Paredes, S. Bonnefoy, Givi N. Kimeridze, Thomas Bretz, E. N. Kopatskaya, M. H. Wu, Antonio Stamerra, K. Frantzen, J. Rico, M. Villata, P. Giammaria, Damir Lelas, Alexander Hahn, Y. Hanabata, E. Forné, F. Di Pierro, Jose Luis Contreras, H. C. Lin, R. López-Coto, I. Snidaric, Daniela Dorner, Dariusz Gora, A. Niedzwiecki, F. Borracci, Gareth Hughes, P. Antoranz, Juan Abel Barrio, Juan Cortina, Saverio Lombardi, L. V. Larionova, Ivan S. Troitsky, David Paneque, Dorota Sobczyńska, P. Temnikov, S. Paiano, Karl Mannheim, B. Biasuzzi, M. Gaug, J. Herrera, Talvikki Hovatta, Junko Kushida, Diego F. Torres, Wolfgang Rhode, D. Guberman, Koji Noda, Elisa Bernardini, M. G. Nikolashvili, P. Da Vela, Francesco Longo, J. Hose, D. Garrido Terrats, J. Becerra González, E. Prandini, A. De Angelis, A. Treves, D. Elsaesser, Vitaly Neustroev, D. Hadasch, Julia Thaele, P. G. Prada Moroni, R. Clavero, Markus Garczarczyk, Valeri M. Larionov, R. Ligustri, H. Takami, W. Bednarek, Julian Sitarek, Fabrizio Tavecchio, J. A. Ros, Abelardo Moralejo, M. Palatiello, Stefano Ansoldi, A. C. Sadun, C. Schultz, Vassil Verguilov, G. Maneva, B. Banerjee, S. Buson, Riccardo Paoletti, T. Steinbring, C. Fruck, Lorand A. Sigua, W. Idec, Ivica Puljak, Francesco Dazzi, A. Fernández-Barral, Pierre Colin, Oscar Blanch, T. S. Grishina, Ana Babić, E. de Oña Wilhelmi, E. Colombo, T. Toyama, O. M. Kurtanidze, G. Bonnoli, Elina Lindfors, Anne Lähteenmäki, M. Hayashida, D. A. Morozova, L. O. Takalo, Masahiro Teshima, Ekaterina Koptelova, A. Sillanpää, B. De Lotto, Ievgen Vovk, L. Maraschi, Tomislav Terzić, T. Schweizer, Reiko Orito, Daniel Mazin, Marc Ribó, P. Bangale, Hidetoshi Kubo, Stefano Covino, Tomoki Saito, D. Tescaro, M. Makariev, B. McBreen, M. I. Martínez, Sabrina Einecke, J. Rodriguez Garcia, K. Mallot, R. J. García López, Massimo Persic, Lluis Font, Marcel Strzys, N. V. Efimova, L. Nogués, Universitat de Barcelona, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Buson, S., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Oña Wilhelmi, E., Di Pierro, F., Domínguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinović, N., González Muñoz, A., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Nogués, L., Orito, R., Overkemping, A, Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Perri, L., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Saito, T., Satalecka, K., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Blinov, D. A., Chen, W. P., Efimova, N. V., Forné, E., Grishina, T. S., Hovatta, T., Jordan, B., Kimeridze, G. N., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O. M., Kurtanidze, S. O., Lähteenmäki, A., Larionov, V. M., Larionova, E. G., Larionova, L. V., Ligustri, R., Lin, H. C., Mcbreen, B., Morozova, D. A., Nikolashvili, M. G., Raiteri, C. M., Ros, J. A., Sadun, A. C., Sigua, L. A., Tornikoski, M., Troitsky, I. S., Villata, M., Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University

Subjects
Astrofísica, Astroparticle physics, BL Lacertae objects: individual: Markarian 421, Radiation mechanisms: non-thermal, Astronomy and Astrophysics, Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Astrophysics, Astroparticle physic, individual: Markarian 421 [BL Lacertae objects], 01 natural sciences, Radiació, law.invention, Telescope, law, 0103 physical sciences, MAGIC (telescope), Blazar, 010303 astronomy & astrophysics, Cherenkov radiation, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, non-thermal [Radiation mechanisms], Radiation, 010308 nuclear & particles physics, Compton scattering, Astronomy and Astrophysic, Light curve, Astrophysics - Astrophysics of Galaxies, astroparticle physics / BL Lacertae objects: individual: Markarian 421 / radiation mechanisms: non-thermal, Astrophysics of Galaxies (astro-ph.GA), ddc:520, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We study the multi-band variability and correlations of the TeV blazar Mrk 421 on year time scales, which can bring additional insight on the processes responsible for its broadband emission. We observed Mrk 421 in the very high energy (VHE) gamma-ray range with the Cherenkov telescope MAGIC-I from March 2007 to June 2009 for a total of 96 hours of effective time after quality cuts. The VHE flux variability is quantified with several methods, including the Bayesian Block algorithm, which is applied to data from Cherenkov telescopes for the first time. The 2.3 year long MAGIC light curve is complemented with data from the Swift/BAT and RXTE/ASM satellites and the KVA, GASP-WEBT, OVRO, and Mets\"ahovi telescopes from February 2007 to July 2009, allowing for an excellent characterisation of the multi-band variability and correlations over year time scales. Mrk 421 was found in different gamma-ray emission states during the 2.3 year long observation period. Flares and different levels of variability in the gamma-ray light curve could be identified with the Bayesian Block algorithm. The same behaviour of a quiet and active emission was found in the X-ray light curves measured by Swift/BAT and the RXTE/ASM, with a direct correlation in time. The behaviour of the optical light curve of GASP-WEBT and the radio light curves by OVRO and Mets\"ahovi are different as they show no coincident features with the higher energetic light curves and a less variable emission. The fractional variability is overall increasing with energy. The comparable variability in the X-ray and VHE bands and their direct correlation during both high- and low-activity periods spanning many months show that the electron populations radiating the X-ray and gamma-ray photons are either the same, as expected in the Synchrotron-Self-Compton mechanism, or at least strongly correlated, as expected in electromagnetic cascades., Comment: Corresponding authors: Ann-Kristin Overkemping (ann-kristin.overkemping@tu-dortmund.de), Marina Manganaro (manganaro@iac.es), Diego Tescaro (diego.tescaro@gmail.com), To be published in Astronomy&Astrophysics (A&A), 12 pages, 9 figures

Published
2016
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44. Multiwavelength observations of the blazar 1ES 1011+496 in Spring 2008

Author

Pierre Colin, E. de Oña Wilhelmi, Kari Nilsson, L. Maraschi, M. Will, Francesco Longo, Tomislav Terzić, Daniela Dorner, C. Pittori, Michael T. Carini, R. Clavero, Louis Antonelli, E. Prandini, Pratik Majumdar, M. V. Fonseca, Mosè Mariotti, K. Kodani, J. Becerra González, W. Bednarek, M. Makariev, M. Palatiello, Ievgen Vovk, Fabrizio Tavecchio, S. N. Shore, M. Gaug, J. Herrera, J. Palacio, J. M. Paredes, Koji Noda, F. Di Pierro, Antonio Stamerra, Thomas Bretz, Elisa Bernardini, Stefano Covino, T. Schweizer, R. Zanin, D. Dominis Prester, A.-K. Overkemping, Adrian Biland, B. Biasuzzi, R. López-Coto, Juri Poutanen, Nikola Godinovic, R. Reinthal, Benito Marcote, Jose Luis Contreras, Saverio Lombardi, S. Rügamer, Marcel Strzys, R. Walters, Junko Kushida, D. Nakajima, Francesco Dazzi, Juan Abel Barrio, A. Niedzwiecki, P. Da Vela, Juan Cortina, Y. Hanabata, S. Bonnefoy, J. Rico, A. González Muñoz, Razmik Mirzoyan, Oscar Blanch, U. Barres de Almeida, P. Antoranz, Tomoki Saito, D. Tescaro, K. Frantzen, P. Temnikov, E. Colombo, Damir Lelas, K. Mallot, David Paneque, J. Sainio, Arka Chatterjee, M. Hayashida, R. J. García López, L. O. Takalo, Kyoshi Nishijima, Wolfgang Rhode, M. H. Wu, D. Guberman, Dorota Sobczyńska, D. Fidalgo, Gareth Hughes, E. Carmona, Markus Garczarczyk, P. G. Prada Moroni, Anne Lähteenmäki, A. De Angelis, Andrei Berdyugin, A. Pease, S. Paiano, Masahiro Teshima, A. Treves, Vitaly Neustroev, D. Garrido Terrats, G. De Caneva, Alba Fernández-Barral, Stefano Ansoldi, Karl Mannheim, Elina Lindfors, M. I. Martínez, Julian Sitarek, Julia Thaele, Riccardo Paoletti, W. Idec, Massimo Persic, C. Schultz, V. Scapin, Yusuke Konno, F. Lucarelli, Daniel Mazin, Marina Manganaro, Marc Ribó, G. Maneva, T. Toyama, S. Vercellone, D. Galindo, Merja Tornikoski, J. E. Ward, Alicia López-Oramas, Ana Babić, Sabrina Einecke, P. Bangale, Reiko Orito, J. Rodriguez Garcia, Christian Fruck, Hidetoshi Kubo, B. De Lotto, A. La Barbera, Konstancja Satalecka, Michele Doro, X. Paredes-Fortuny, J. Hose, D. Elsaesser, M. Nievas Rosillo, H. Takami, B. Banerjee, D. Glawion, Vassil Verguilov, U. Menzel, Diego F. Torres, M. Pasanen, Abelardo Moralejo, A. Sillanpää, T. Steinbring, Ll. Font, I. Snidaric, E. Lorenz, Max Ludwig Ahnen, P. Giammaria, G. Bonnoli, Dario Hrupec, M. A. Lopez, F. Borracci, C. Delgado Mendez, Alessandro Carosi, Jose Miguel Miranda, Ivica Puljak, Glawion, D., Universitat de Barcelona, Ahnen, M. L, Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., De Oña Wilhelmi, E., Delgado Mendez, C., Di Pierro, F., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinović, N., González Muñoz, A., Guberman, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., López Oramas, A., Lorenz, E., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Rügamer, S., Saito, T., Satalecka, K., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Lucarelli, F., Pittori, C., Vercellone, S., Berdyugin, A., Carini, M. T., Lähteenmäki, A., Pasanen, M., Pease, A., Sainio, J., Tornikoski, M., Walters, R., Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University

Subjects
galaxie [X-rays], galaxie [Gamma-rays], Radiation mechanisms: non-thermal, radiation mechanisms: non-thermal, galaxies: active, gamma-rays, galaxies, X-rays: galaxies, BL-LACERTAE OBJECTS, ACTIVE GALACTIC NUCLEI, LARGE-AREA TELESCOPE, GAMMA-RAY EMISSION, SPECTRAL ENERGY-DISTRIBUTIONS, ALL-SKY SURVEY, LAC, OBJECTS, X-RAY, MAGIC TELESCOPES, SOURCE CATALOG, Astrophysics, Galaxies: active, Gamma-rays: galaxies, Astronomy and Astrophysics, Space and Planetary Science, 01 natural sciences, Radiació, law.invention, law, MAGIC (telescope), 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Spectral index, Radiation, Gamma ray, galaxies [Gamma-rays], galaxies [X-rays], Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Flare, BL Lac object, Active galactic nucleus, radiation mechanisms, non-thermal galaxies, active gamma-rays, galaxies X-rays, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, 0103 physical sciences, Blazar, ta115, non-thermal [Radiation mechanisms], 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysic, Light curve, Galàxies actives, Active galaxies, ddc:520
Abstract

The BL Lac object 1ES 1011+496 was discovered at Very High Energy gamma-rays by MAGIC in spring 2007. Before that the source was little studied in different wavelengths. Therefore a multi-wavelength (MWL) campaign was organized in spring 2008. Along MAGIC, the MWL campaign included the Metsahovi radio observatory, Bell and KVA optical telescopes and the Swift and AGILE satellites. MAGIC observations span from March to May, 2008 for a total of 27.9 hours, of which 19.4 hours remained after quality cuts. The light curve showed no significant variability. The differential VHE spectrum could be described with a power-law function. Both results were similar to those obtained during the discovery. Swift XRT observations revealed an X-ray flare, characterized by a harder when brighter trend, as is typical for high synchrotron peak BL Lac objects (HBL). Strong optical variability was found during the campaign, but no conclusion on the connection between the optical and VHE gamma-ray bands could be drawn. The contemporaneous SED shows a synchrotron dominated source, unlike concluded in previous work based on nonsimultaneous data, and is well described by a standard one zone synchrotron self Compton model. We also performed a study on the source classification. While the optical and X-ray data taken during our campaign show typical characteristics of an HBL, we suggest, based on archival data, that 1ES 1011+496 is actually a borderline case between intermediate and high synchrotron peak frequency BL Lac objects., 13 pages, accepted for publication in MNRAS

Published
2016
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45. Insights into the emission of the blazar 1ES 1011+496 through unprecedented broadband observations during 2011 and 2012

Author

Daniela Dorner, E. Prandini, Iain A. Steele, Francesco Dazzi, M. Gaug, J. Herrera, A. Fernández-Barral, M. V. Fonseca, Koji Noda, Elisa Bernardini, E. Colombo, F. Di Pierro, S. Bonnefoy, M. Makariev, Talvikki Hovatta, Ivica Puljak, Pierre Colin, L. O. Takalo, D. Garrido Terrats, J. L. Richards, E. de Oña Wilhelmi, Roberta Zanin, Mosè Mariotti, A.-K. Overkemping, D. Eisenacher, E. Carmona, Markus Garczarczyk, J. Krause, B. De Lotto, Natalia Lewandowska, P. Da Vela, D. Nakajima, M. Hayashida, V. Scalzotto, U. Menzel, R. Reinthal, Juan Abel Barrio, Carole Mundell, Razmik Mirzoyan, U. Barres de Almeida, Abelardo Moralejo, Damir Lelas, K. Nishijima, Saverio Lombardi, P. G. Prada Moroni, Michele Palatiello, T. Schweizer, C. Delgado Mendez, T. Steinbring, P. Temnikov, D. Fidalgo, Anthony C. S. Readhead, Hanna Kellermann, M. I. Martínez, P. Bangale, Dorota Sobczyńska, A. De Angelis, A. Treves, Vitaly Neustroev, D. Dominis Prester, Francesco Longo, A. La Barbera, Juri Poutanen, Ana Babić, Stefano Ansoldi, Sabrina Einecke, S. R. Gozzini, Stefano Covino, Riccardo Paoletti, Nikola Godinovic, Benito Marcote, Elizaveta Rastorgueva-Foi, M. Strzys, Yusuke Konno, Y. Hanabata, Marc Ribó, J. Rodriguez Garcia, M. Nievas Rosillo, Jelena Aleksić, Kazuo Saito, J. Kushida, P. Antoranz, M. L. Knoetig, R. López-Coto, Diego F. Torres, G. Maneva, Antonio Stamerra, A. Niedzwiecki, Hidetoshi Kubo, S. N. Shore, X. Paredes-Fortuny, Jose Luis Contreras, Adrian Biland, Alessandro Carosi, W. Idec, David Sánchez, B. Biasuzzi, D. Tescaro, Tuomas Savolainen, David Paneque, P. Munar-Adrover, Julian Sitarek, K. Frantzen, J. Rico, I. Lozano, C. Fruck, T. Toyama, G. De Caneva, Juan Cortina, Anne Lähteenmäki, Oscar Blanch, K. Kodani, Masahiro Teshima, D. Hadasch, V. Kadenius, Elina Lindfors, Merja Tornikoski, Alexander B. Pushkarev, Daniel Mazin, Matthew L. Lister, Julia Thaele, Konstancja Satalecka, Louis Antonelli, Michele Doro, S. Paiano, Joni Tammi, F. D'Ammando, G. Bonnoli, K. Mallot, Karl Mannheim, Jose Miguel Miranda, R. J. García López, J. Hose, Massimo Persic, A. Sillanpää, D. Elsaesser, Takashi Saito, H. Takami, Eckart Lorenz, Alicia López-Oramas, V. Scapin, Reiko Orito, D. Galindo, J. Becerra González, Dario Hrupec, M. A. Lopez, F. Borracci, J. M. Paredes, A. González Mu. noz, Yuri Y. Kovalev, Kari Nilsson, S. Buson, M. Will, C. Arcaro, I. Snidaric, Thomas Bretz, L. Maraschi, Walter Max-Moerbeck, Tomislav Terzić, Wolfgang Rhode, Patrick Vogler, W. Bednarek, Fabrizio Tavecchio, Ll. Font, Aleksic J, Ansoldi S, Antonelli LA, Antoranz P, Arcaro C, Babic A, Bangale P, de Almeida UB, Barrio JA, Gonzalez JB, Bednarek W, Bernardini E, Biasuzzi B, Biland A, Blanch O, Bonnefoy S, Bonnoli G, Borracci F, Bretz T, Carmona E, Carosi A, Colin P, Colombo E, Contreras JL, Cortina J, Covino S, Da Vela P, Dazzi F, De Angelis A, De Caneva G, De Lotto B, Wilhelmi ED, Mendez CD, Di Pierro F, Prester DD, Dorner D, Doro M, Einecke S, Eisenacher D, Elsaesser D, Fernandez-Barral A, Fidalgo D, Fonseca MV, Font L, Frantzen K, Fruck C, Galindo D, Lopez RJG, Garczarczyk M, Terrats DG, Gaug M, Godinovic N, Munoz AG, Gozzini SR, Hadasch D, Hanabata Y, Hayashida M, Herrera J, Hose J, Hrupec D, Idec W, Kadenius V, Kellermann H, Knoetig ML, Kodani K, Konno Y, Krause J, Kubo H, Kushida J, La Barbera A, Lelas D, Lewandowska N, Lindfors E, Lombardi S, Longo F, Lopez M, Lopez-Coto R, Lopez-Oramas A, Lorenz E, Lozano I, Makariev M, Mallot K, Maneva G, Mannheim K, Maraschi L, Marcote B, Mariotti M, Martinez M, Mazin D, Menzel U, Miranda JM, Mirzoyan R, Moralejo A, Munar-Adrover P, Nakajima D, Neustroev V, Niedzwiecki A, Rosillo MN, Nilsson K, Nishijima K, Noda K, Orito R, Overkemping A, Paiano S, Palatiello M, Paneque D, Paoletti R, Paredes JM, Paredes-Fortuny X, Persic M, Poutanen J, Moroni PGP, Prandini E, Puljak I, Reinthal R, Rhode W, Ribo M, Rico J, Garcia JR, Saito T, Saito K, Satalecka K, Scalzotto V, Scapin V, Schweizer T, Shore SN, Sillanpaa A, Sitarek J, Snidaric I, Sobczynska D, Stamerra A, Steinbring T, Strzys M, Takalo L, Takami H, Tavecchio F, Temnikov P, Terzic T, Tescaro D, Teshima M, Thaele J, Torres DF, Toyama T, Treves A, Vogler P, Will M, Zanin R, Buson S, DAmmando F, Lateenmaki A, Hovatta T, Kovalev YY, Lister ML, Max-Moerbeck W, Mundell C, Pushkarev AB, Rastorgueva-Foi E, Readhead ACS, Richards JL, Tammi J, Sanchez DA, Tornikoski M, Savolainen T, Steele I, Autonomous University of Barcelona, University of Udine, INAF, Osservatorio Astronomico di Roma, University of Siena, University of Padova, University of Rijeka, Max Planck Institute for Physics, Centro Brasileiro de Pesquisas Físicas, Complutense University, University of Maryland, College Park, University of Łódź, Deutsches Elektronen-Synchrotron, Swiss Federal Institute of Technology Zurich, University of Würzburg, CIEMAT, Instituto de Astrofísica de Canarias, Institute of Space Studies of Catalonia, Technische Universität Dortmund, University of Barcelona, Kyoto University, Finnish MAGIC Consortium, Institute for Nuclear Research and Nuclear Energy, Japanese MAGIC Consortium, University of Turku, University of Pisa, Max-Planck-Institut für Physik, ICREA, University of Insubria, Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, Department of Radio Science and Engineering, California Institute of Technology, Lebedev Physical Institute, Purdue University, National Radio Astronomy Observatory Socorro, University of Liverpool, Crimean Astrophysical Observatory, Max Planck Institute for Radio Astronomy, Metsähovi Radio Observatory, Université Savoie Mont Blanc, Max-Planck-Institut für Radioastronomie, Aalto-yliopisto, Aalto University, Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Arcaro, C, Babic, A., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., De Oña Wilhelmi, E., Delgado Mendez, C., Di Pierro, F., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Godinović, N., González Muñoz, A., Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., López Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar Adrover, P., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Will, M., Zanin, R., Buson, S., D'Ammando, F., Lähteenmäki, A., Hovatta, T., Kovalev, Y. Y., Lister, M. L., Max Moerbeck, W., Mundell, C., Pushkarev, A. B., Rastorgueva Foi, E., Readhead, A. C. S., Richards, J. L., Tammi, J., Sanchez, D. A., Tornikoski, M., Savolainen, T., Steele, I., Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and Universitat de Barcelona

Subjects
Photon, jets [galaxies], Astrophysics, 7. Clean energy, 01 natural sciences, LARGE-AREA TELESCOPE, law.invention, law, BL Lacertae objects: individual: 1ES 1011+496, galaxies: active, galaxies: jets, gamma rays: galaxies, radiation mechanisms: non-thermal, Astronomy and Astrophysics, Space and Planetary Science, individual: 1ES 1011+496 [BL Lacertae objects], 010303 astronomy & astrophysics, QC, QB, Physics, astro-ph.HE, High Energy Astrophysical Phenomena (astro-ph.HE), Superluminal motion, TEV BLAZARS, Polarization (waves), non-thermal [radiation mechanisms], Cosmology, BL-LACERTAE OBJECTS, ACTIVE GALACTIC NUCLEI, GAMMA-RAY EMISSION, X-RAY, LAC OBJECTS, MAGIC TELESCOPE, CRAB-NEBULA, ENERGY-DISTRIBUTION, active [galaxies], galaxies [gamma rays], Spectral energy distribution, Degree of polarization, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Telescope, 0103 physical sciences, galaxie [gamma rays], Blazar, Cosmologia, 010308 nuclear & particles physics, Astronomy and Astrophysic, Position angle, Galaxies, Galàxies, jet [galaxies], ddc:520, BL Lacertae objects: individual: 1ES 1011+496 – galaxies: active – galaxies: jets – radiation mechanisms: non-thermal – gamma rays: galaxies
Abstract

1ES 1011+496 $(z=0.212)$ was discovered in very high energy (VHE, E >100 GeV) $\gamma$-rays with MAGIC in 2007. The absence of simultaneous data at lower energies led to a rather incomplete characterization of the broadband spectral energy distribution (SED). We study the source properties and the emission mechanisms, probing whether a simple one-zone synchrotron-self-Compton (SSC) scenario is able to explain the observed broadband spectrum. We analyzed VHE to radio data from 2011 and 2012 collected by MAGIC, $Fermi$-LAT, $Swift$, KVA, OVRO, and Mets\"ahovi in addition to optical polarimetry data and radio maps from the Liverpool Telescope and MOJAVE. The VHE spectrum was fit with a simple power law with a photon index of $3.69\pm0.22$ and a flux above 150 GeV of $(1.46\pm0.16)\times10^{-11}$ ph cm$^{-2}$ s$^{-1}$. 1ES 1011+496 was found to be in a generally quiescent state at all observed wavelengths, showing only moderate variability from radio to X-rays. A low degree of polarization of less than 10% was measured in optical, while some bright features polarized up to 60% were observed in the radio jet. A similar trend in the rotation of the electric vector position angle was found in optical and radio. The radio maps indicated a superluminal motion of $1.8\pm0.4\,c$, which is the highest speed statistically significantly measured so far in a high-frequency-peaked BL Lac. For the first time, the high-energy bump in the broadband SED of 1ES 1011+496 could be fully characterized from 0.1 GeV to 1 TeV which permitted a more reliable interpretation within the one-zone SSC scenario. The polarimetry data suggest that at least part of the optical emission has its origin in some of the bright radio features, while the low polarization in optical might be due to the contribution of parts of the radio jet with different orientations of the magnetic field to the optical emission., Comment: 14 pages, 7 figures

Published
2016
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46. Orbital and superorbital variability of LS I +61 303 at low radio frequencies with GMRT and LOFAR

Author

Jochen Eislöffel, Heino Falcke, M. Pietka, D. Carbone, Jean-Mathias Grießmeier, Ph. Zarka, A. J. van der Horst, J. van Leeuwen, Adam Stewart, Rene P. Breton, Sera Markoff, Michael W. Wise, John D. Swinbank, Stephane Corbel, Marc Ribó, M. Kuniyoshi, Martin Bell, Ralph A. M. J. Wijers, Guy G. Pooley, J. W. Broderick, Benito Marcote, Rob Fender, C. H. Ishwara-Chandra, M. Serylak, J. M. Paredes, Antonia Rowlinson, Universitat de Barcelona, Departament d'Astronomia i Meteorologia [Barcelona] (DAM), Universitat de Barcelona (UB), National Centre for Radio Astrophysics [Pune] (NCRA), Tata Institute of Fundamental Research [Bombay] (TIFR), Department of Astrophysical Sciences [Princeton], Princeton University, Oxford Astrophysics, University of Oxford [Oxford], Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Mullard Radio Astronomy Observatory (MRAO), University of Cambridge [UK] (CAM), University of Southampton, Jodrell Bank Centre for Astrophysics, University of Manchester [Manchester], Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Unité Scientifique de la Station de Nançay (USN), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Thüringer Landessternwarte Tautenburg (TLS), Radboud university [Nijmegen], Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Max-Planck-Institut für Radioastronomie (MPIFR), Netherlands Institute for Radio Astronomy (ASTRON), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), NASA grants NNX08AW31G and NNX11A043G, and NSF grants AST-0808050 and AST-1109911Spanish Ministerio de Econom´ıa y Competitividad (MINECO) under grants AYA2013-47447-C3-1-P, FPA2013-48381-C6-6-P, MDM-2014-0369 of ICCUB (Unidad de Excelencia ‘Mar´ıa de Maeztu’), and the Catalan DEC grant 2014 SGR 86., ANR-11-IDEX-0005-02/10-LABX-0023,UnivEarthS,Earth - Planets - Universe: observation, modeling, transfer(2011), European Project: 267697,EC:FP7:ERC,ERC-2010-AdG_20100224,4PI-SKY(2011), European Project: 332393,EC:FP7:PEOPLE,FP7-PEOPLE-2012-IIF,FAST TRANSIENTS(2014), Tata Institute for Fundamental Research (TIFR), University of Oxford, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Radboud University [Nijmegen], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), ANR-11-IDEX-0005,USPC,Université Sorbonne Paris Cité(2011), High Energy Astrophys. & Astropart. Phys (API, FNWI), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), and Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)

Subjects
Astrofísica, 010504 meteorology & atmospheric sciences, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], media_common.quotation_subject, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Binary number, Estels binaris, Astrophysics, 01 natural sciences, Raigs gamma, Double stars, 0103 physical sciences, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Gamma rays, Astronomy and Astrophysics, LOFAR, radiation mechanisms: non-thermal – binaries: close – stars: individual: LS I + 61 303 – gamma-rays: stars – radio continuum: stars, Space and Planetary Science, Sky, Modulation, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Radio frequency, Maxima, Astrophysics - High Energy Astrophysical Phenomena
Abstract

LS I +61 303 is a gamma-ray binary that exhibits an outburst at GHz frequencies each orbital cycle of $\approx$ 26.5 d and a superorbital modulation with a period of $\approx$ 4.6 yr. We have performed a detailed study of the low-frequency radio emission of LS I +61 303 by analysing all the archival GMRT data at 150, 235 and 610 MHz, and conducting regular LOFAR observations within the Radio Sky Monitor (RSM) at 150 MHz. We have detected the source for the first time at 150 MHz, which is also the first detection of a gamma-ray binary at such a low frequency. We have obtained the light-curves of the source at 150, 235 and 610 MHz, all of them showing orbital modulation. The light-curves at 235 and 610 MHz also show the existence of superorbital variability. A comparison with contemporaneous 15-GHz data shows remarkable differences with these light-curves. At 15 GHz we see clear outbursts, whereas at low frequencies we see variability with wide maxima. The light-curve at 235 MHz seems to be anticorrelated with the one at 610 MHz, implying a shift of $\sim$ 0.5 orbital phases in the maxima. We model the shifts between the maxima at different frequencies as due to changes in the physical parameters of the emitting region assuming either free-free absorption or synchrotron self-absorption, obtaining expansion velocities for this region close to the stellar wind velocity with both mechanisms., 12 pages, 10 figures, accepted for publication in MNRAS

Published
2015
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47. Physical properties of the gamma-ray binary LS 5039 through low and high frequency radio observations

Author

J. M. Paredes, Benito Marcote, Marc Ribó, and C. H. Ishwara-Chandra

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Electron density, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Synchrotron, Spectral line, Radio spectrum, law.invention, Magnetic field, Pulsar, Relativistic plasma, Space and Planetary Science, law, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract

We have studied in detail the 0.15-15 GHz radio spectrum of the gamma-ray binary LS 5039 to look for a possible turnover and absorption mechanisms at low frequencies, and to constrain the physical properties of its emission. We have analysed two archival VLA monitorings, all the available archival GMRT data and a coordinated quasi-simultaneous observational campaign conducted in 2013 with GMRT and WSRT. The data show that the radio emission of LS 5039 is persistent on day, week and year timescales, with a variability $\lesssim 25~\%$ at all frequencies, and no signature of orbital modulation. The obtained spectra reveal a power-law shape with a curvature below 5 GHz and a turnover at $\sim0.5$ GHz, which can be reproduced by a one-zone model with synchrotron self-absorption plus Razin effect. We obtain a coherent picture for a size of the emitting region of $\sim0.85~\mathrm{mas}$, setting a magnetic field of $B\sim20~\mathrm{mG}$, an electron density of $n_{\rm e}\sim4\times10^5~{\rm cm^{-3}}$ and a mass-loss rate of $\dot M\sim5\times10^{-8}~{\rm M_{\odot} yr^{-1}}$. These values imply a significant mixing of the stellar wind with the relativistic plasma outflow from the compact companion. At particular epochs the Razin effect is negligible, implying changes in the injection and the electron density or magnetic field. The Razin effect is reported for first time in a gamma-ray binary, giving further support to the young non-accreting pulsar scenario., 16 pages, 9 figures, accepted for publication in MNRAS

Published
2015

48. Very high-energy gamma-ray observations of novae and dwarf novae with the MAGIC telescopes

Author

J. Kushida, Jose Luis Contreras, Juan Cortina, Tomislav Terzić, A. De Angelis, A. Treves, Vitaly Neustroev, M. Hayashida, Marc Ribó, Marina Manganaro, P. Bangale, D. Galindo, Hidetoshi Kubo, B. Biasuzzi, Abelardo Moralejo, H. Takami, Vassil Verguilov, G. Maneva, D. Nakajima, Konstancja Satalecka, Michele Doro, Giacomo Bonnoli, Julia Thaele, M. I. Martínez, R. Zanin, Adrian Biland, Arka Chatterjee, P. G. Prada Moroni, T. Steinbring, D. Fidalgo, K. Mallot, R. J. García López, J. Rico, M. Palatiello, Kyoshi Nishijima, Yusuke Konno, Sabrina Einecke, Pratik Majumdar, R. Reinthal, Francesco Dazzi, Gareth Hughes, M. V. Fonseca, K. Kodani, C. Schultz, V. Scapin, J. Rodriguez Garcia, Dominik Elsaesser, U. Barres de Almeida, R. Desiante, Stefano Covino, R. López-Coto, B. Banerjee, Max Ludwig Ahnen, Stefano Ansoldi, A. Niedzwiecki, Riccardo Paoletti, G. De Caneva, Damir Lelas, Massimo Persic, D. Tescaro, David Paneque, K. Saito, J. Palacio, Ievgen Vovk, D. Guberman, Dorota Sobczyńska, Julian Sitarek, J. M. Paredes, Antonio Stamerra, P. Giammaria, L. Maraschi, Nikola Godinovic, Benito Marcote, E. Hays, Elina Lindfors, J. Hose, Daniel Mazin, T. Toyama, Hanna Kellermann, B. De Lotto, T. Schweizer, D. Dominis Prester, Ivica Puljak, S. Bonnefoy, R. Clavero, P. Temnikov, Pierre Colin, L. A. Antonelli, Kari Nilsson, M. Will, K. Frantzen, Thomas Bretz, F. Di Pierro, R. Mirzoyan, Juri Poutanen, D. Garrido Terrats, P. Da Vela, Wlodek Bednarek, Alessandro Carosi, E. de Oña Wilhelmi, Y. Hanabata, J. A. Barrio, P. Antoranz, E. Carmona, Masahiro Teshima, S. Paiano, Wolfgang Rhode, Karl Mannheim, Jose Miguel Miranda, Fabrizio Tavecchio, Alicia López-Oramas, Ana Babić, F. Borracci, I. Snidaric, Natalia Lewandowska, A. La Barbera, D. Eisenacher Glawion, X. Paredes-Fortuny, M. Nievas Rosillo, E. Lorenz, J. Becerra González, Takashi Saito, Reiko Orito, E. Prandini, U. Menzel, Daniela Dorner, Diego F. Torres, M. Garczarczyk, A. Sillanpää, E. Colombo, M. Gaug, J. Herrera, L. O. Takalo, Francesco Longo, Koji Noda, Elisa Bernardini, Lluis Font, Marcel Strzys, Martin Makariev, Oscar Blanch, Alba Fernández-Barral, W. Idec, Christian Fruck, Mosè Mariotti, A.-K. Overkemping, Dario Hrupec, M. A. Lopez, A. González Muñoz, Saverio Lombardi, C. Delgado Mendez, Ahnen, M. L, Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., De Oña Wilhelmi, E., Delgado Mendez, C., Di Pierro, F., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinović, N., González Muñoz, A., Guberman, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kellermann, H., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., López Oramas, A., Lorenz, E., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Saito, T., Saito, K., Satalecka, K., Scapin, V., Schultz, C., Schweizer, T., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Will, M., Zanin, R., Desiante, R., Hays, E., and Universitat de Barcelona

Subjects
Proton, Hadron, Astrophysics, 01 natural sciences, 7. Clean energy, law.invention, Raigs gamma, law, Astrophysics::Solar and Stellar Astrophysics, novae, cataclysmic variables, gamma rays: stars, binaries: general, stars: activity, 010303 astronomy & astrophysics, Dwarf nova, Novae, Estels binaris de raigs X, astro-ph.HE, Physics, Novae, cataclysmic variable, cataclysmic variables, Binaries: general, Gamma rays: stars, Novae, cataclysmic variables, Stars: activity, Astronomy and Astrophysics, Space and Planetary Science, Gamma-rays, stars, Binaries, general, Stars, activity, Gamma ray, X-ray binaries, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, activity [Stars], Astrophysics::High Energy Astrophysical Phenomena, Noves (Estels), Telescope, star [Gamma rays], 0103 physical sciences, New stars, general [Binaries], 010308 nuclear & particles physics, Gamma rays, Astronomy and Astrophysic, 13. Climate action, ddc:520, High Energy Physics::Experiment, Fermi Gamma-ray Space Telescope, Lepton
Abstract

Context. In the last five years the Fermi Large Area Telescope (LAT) instrument detected GeV {\gamma}-ray emission from five novae. The GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a shock. In this case it is expected that protons in the same conditions can be accelerated to much higher energies. Consequently they may produce a second component in the {\gamma}-ray spectrum at TeV energies. Aims. We aim to explore the very-high-energy domain to search for {\gamma}-ray emission above 50 GeV and to shed light on the acceleration process of leptons and hadrons in nova explosions. Methods. We have performed observations with the MAGIC telescopes of the classical nova V339 Del shortly after the 2013 outburst, triggered by optical and subsequent GeV {\gamma}-ray detec- tions. We also briefly report on VHE observations of the symbiotic nova YY Her and the dwarf nova ASASSN-13ax. We complement the TeV MAGIC observations with the analysis of con- temporaneous Fermi-LAT data of the sources. The TeV and GeV observations are compared in order to evaluate the acceleration parameters for leptons and hadrons. Results. No significant TeV emission was found from the studied sources. We computed upper limits on the spectrum and night-by-night flux. The combined GeV and TeV observations of V339 Del limit the ratio of proton to electron luminosities to Lp, Comment: 7 pages, 2 figures, accepted for publication in A&A

Published
2015
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49. Towards the origin of the radio emission in AR Scorpii, the first radio-pulsing white dwarf binary

Author

Benito Marcote, Zsolt Paragi, J. M. Blanchard, Elizabeth R. Stanway, and T. R. Marsh

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Synchrotron radiation, Flux, Magnetosphere, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Collimated light, law.invention, Telescope, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, White dwarf, Astronomy and Astrophysics, Light curve, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The binary system AR Sco contains an M star and the only known radio-pulsing white dwarf. The system shows emission from radio to X-rays, likely dominated by synchrotron radiation. The mechanism that produces most of this emission remains unclear. Two competing scenarios have been proposed: Collimated outflows, and direct interaction between the magnetospheres of the white dwarf and the M star. The two proposed scenarios can be tested via very long baseline interferometric radio observations. We conducted a radio observation with the Australian Long Baseline Array (LBA) on 20 Oct 2016 at 8.5 GHz to study the compactness of the radio emission. Simultaneous data with the Australian Telescope Compact Array (ATCA) were also recorded for a direct comparison of the obtained flux densities. AR Sco shows radio emission compact on milliarcsecond angular scales ($\lesssim 0.02\ \mathrm{AU}$, or $4\ \mathrm{R_{\odot}}$). The emission is orbitally modulated, with an average flux density of $\approx 6.5\ \mathrm{mJy}$. A comparison with the simultaneous ATCA data shows that no flux is resolved out on mas scales, implying that the radio emission is produced in this compact region. Additionally, the obtained radio light curves on hour timescales are consistent with the optical light curve. The radio emission in AR Sco is likely produced in the magnetosphere of the M star or the white dwarf, and we see no evidence for a radio outflow or collimated jets significantly contributing to the radio emission., 4 pages, 2 figures, accepted for publication in A&A

Published
2017
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50. Black hole lightning due to particle acceleration at subhorizon scales

Author

J. Kushida, Jose Luis Contreras, Juan Cortina, J. Hose, R. Reinthal, D. Elsaesser, Michele Palatiello, P. Munar-Adrover, Elina Lindfors, Damir Lelas, Dario Hrupec, R. Zanin, Daniel Mazin, D. Nakajima, Victor Stamatescu, M. A. Lopez, Dorota Sobczyńska, Adrian Biland, K. Nishijima, M. Uellenbeck, D. Garrido Terrats, D. Dominis Prester, J. Rico, V. Scalzotto, Christian Fruck, E. Prandini, Stefano Covino, P. G. Prada Moroni, Francesco Longo, F. Borracci, P. Da Vela, Nikola Godinovic, Benito Marcote, Patrick Vogler, Ana Babić, D. Galindo, Yusuke Konno, O. Tibolla, I. Snidaric, M. Makariev, D. Tescaro, P. Temnikov, Ivica Puljak, M. V. Fonseca, A. Sillanpää, Jörn Wilms, G. Bonnoli, L. Maraschi, Pierre Colin, C. Delgado Mendez, S. R. Gozzini, E. de Oña Wilhelmi, Konstancja Satalecka, Julian Sitarek, Michele Doro, A. Treves, Kari Nilsson, Tomislav Terzić, N. Mankuzhiyil, Daniela Hadasch, Jelena Aleksić, Oscar Blanch, Alessandro Carosi, E. Lorenz, Ruben Lopez-Coto, T. Toyama, A. Niedzwiecki, I. Lozano, G. De Caneva, M. Hayashida, David Paneque, S. Bonnefoy, A. González Muñoz, T. Schweizer, Jose Miguel Miranda, E. Colombo, Francesco Dazzi, Masahiro Teshima, G. Maneva, Felix Spanier, Y. Hanabata, Daniela Dorner, C. Schultz, V. Scapin, Miriam Lucio Martinez, S. Rügamer, Juan Abel Barrio, M. Gaug, W. Bednarek, Fabrizio Tavecchio, Ll. Font, Juri Poutanen, Stefano Ansoldi, J. Herrera, Koji Noda, B. Biasuzzi, U. Bach, Marc Ribó, Riccardo Paoletti, P. Antoranz, Elisa Bernardini, Hajime Takami, P. Bangale, J. M. Paredes, Felicia Krauß, Hidetoshi Kubo, Antonio Stamerra, Julia Thaele, K. Kodani, E. Carmona, L. O. Takalo, Louis Antonelli, J. Storz, A. De Angelis, D. Hildebrand, Mosè Mariotti, A.-K. Overkemping, Sabrina Einecke, Saverio Lombardi, J. Rodriguez Garcia, K. Saito, W. Idec, K. Frantzen, V. Kadenius, S. Paiano, Karl Mannheim, Alicia López-Oramas, Natalia Lewandowska, R. Mirzoyan, A. La Barbera, D. Eisenacher, Markus Garczarczyk, X. Paredes-Fortuny, J. Becerra González, Abelardo Moralejo, T. Steinbring, Hanna Kellermann, U. Menzel, Diego F. Torres, J. Krause, B. De Lotto, Takashi Saito, Reiko Orito, Eduardo Ros, Marcel Strzys, Matthias Kadler, K. Mallot, R. J. García López, Massimo Persic, R. Schulz, Thomas Bretz, S. N. Shore, Wolfgang Rhode, Aleksić, J, Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Bil, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., De Oña Wilhelmi, E., Mendez, C. Delgado, Prester, D. Domini, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinoviæ, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hildebr, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., Barbera, A. La, Lelas, D., Lewowska, N., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., López Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Mira, J. M., Mirzoyan, R., Moralejo, A., Munar Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Zanin, R., Kadler, M., Schulz, R., Ros, E., Bach, U., Krauß, F., and Wilms, J.

Subjects
Black Holes, Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Very High Energy Gamma Astronomy, Black Holes, Very High Energy Gamma Astronomy, Active Galactic Nuclei, X-shaped radio galaxy, supermassive black hole, jet formation, IC 310, MAGIC telescopes, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Supermassive black hole, ta115, Multidisciplinary, Active Galactic Nuclei, Astronomy and Astrophysics, Galaxy, Intermediate-mass black hole, Stellar black hole, Electrónica, Física nuclear, ddc:500, Spin-flip, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Schwarzschild radius
Abstract

Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry, but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here, we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC telescopes revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20\% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet., 19 pages, 10 figures, includes Supplementary Materials

Published
2014
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