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11 results on '"Josefa Becerra González"'

1. Detection of a Peculiar Drift in the Nuclear Radio Jet of the TeV Blazar Markarian 501

Author

Silke Britzen, Gopal Krishna, Emma Kun, Héctor Olivares, Ilya Pashchenko, Frédéric Jaron, Josefa Becerra González, and David Paneque

Subjects
active galactic nuclei, relativistic jets, multiwavelength observations, theoretical emission models, polarization, jet formation, Elementary particle physics, QC793-793.5
Abstract

Mrk 501 is one of the most prominent TeV-emitting blazars and belongs to the class of high synchrotron peaked (HSP) blazars. The Doppler factors derived from the jet kinematics are much too low to provide sufficient beaming for the detected high-energy emission (the so-called Lorentz factor crisis). This BL Lac object is also a prime example of a misaligned AGN with an approximately 90∘ difference in orientation between the inner parsec-scale jet and the kpc-scale jet structure. We have performed a detailed analysis of the pc-scale jet kinematics, based on 23 years of VLBA observations (at 15 GHz) and find, in addition to robustly consolidating the already claimed stationary jet features and a hinted absence of component ejections, a significant drift of the outer nuclear jet. The two outermost jet features move with somewhat higher but still subluminal speeds. Albeit, they move orthogonally to the inner jet, which itself does not partake in the drifting motion. The effect of this intriguing kinematics is that the jet appears strongly curved at first (1995) but then appears to straighten out (2018). To our knowledge, this is the first time that the orthogonal swing of just the outer part of a nuclear jet has been observed. We discuss the possible physical nature of this turning maneuver. In addition, we report evidence for jet emission, which most likely originates in a spine–sheath structure.

Published
2023
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2. Follow-up Survey for the Binary Black Hole Merger GW200224_222234 Using Subaru/HSC and GTC/OSIRIS

Author

Takayuki Ohgami, Josefa Becerra González, Nozomu Tominaga, Tomoki Morokuma, Yousuke Utsumi, Yuu Niino, Masaomi Tanaka, Smaranika Banerjee, Frédérick Poidevin, Jose Antonio Acosta-Pulido, Ismael Pérez-Fournon, Teo Muñoz-Darias, Hiroshi Akitaya, Kenshi Yanagisawa, Mahito Sasada, Michitoshi Yoshida, Mirko Simunovic, Ryou Ohsawa, Ichi Tanaka, Tsuyoshi Terai, Yuhei Takagi, and The J-GEM collaboration

Subjects
Black holes, Gravitational waves, Surveys, Astrophysics, QB460-466
Abstract

The LIGO/Virgo detected a gravitational wave (GW) event, named GW200224_222234 (also known as S200224ca) and classified as a binary-black hole coalescence, on 2020 February 24. Given its relatively small localization skymap (71 deg ^2 for a 90% credible region; revised to 50 deg ^2 in GWTC-3), we performed target-of-opportunity observations using the Subaru/Hyper Suprime-Cam (HSC) in the r 2 and z bands. Observations were conducted on 2020 February 25 and 28 and March 23, with the first epoch beginning 12.3 hr after the GW detection. The survey covered the highest-probability sky area of 56.6 deg ^2 , corresponding to a 91% probability. This was the first deep follow-up ( m _r ≳ 24, m _z ≳ 23) for a binary-black hole merger covering >90% of the localization. By performing image subtraction and candidate screening including light-curve fitting with transient templates and examples, we found 22 off-nucleus transients that were not ruled out as the counterparts of GW200224_222234 with our Subaru/HSC data alone. We also performed GTC/OSIRIS spectroscopy of the probable host galaxies for five candidates; two are likely to be located within the 3D skymap, whereas the others are not. In conclusion, 19 transients remain as possible optical counterparts of GW200224_222234; but we could not identify a unique promising counterpart. If there are no counterparts in the remaining candidates, the upper limits of the optical luminosity are $\nu {L}_{\nu }\lt {5.2}_{-1.9}^{+2.4}\times {10}^{41}$ erg s ^−1 and $\nu {L}_{\nu }\lt {1.8}_{-0.6}^{+0.8}\times {10}^{42}$ erg s ^−1 in the r 2 and z bands, respectively, at ∼12 hr after GW detection. We also discuss improvements in the strategies of optical follow-ups for future GW events.

Published
2023
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3. A Reemerging Bright Soft X-Ray State of the Changing-look Active Galactic Nucleus 1ES 1927+654: A Multiwavelength View

Author

Ritesh Ghosh, Sibasish Laha, Eileen Meyer, Agniva Roychowdhury, Xiaolong Yang, J. A. Acosta–Pulido, Suvendu Rakshit, Shivangi Pandey, Josefa Becerra González, Ehud Behar, Luigi C. Gallo, Francesca Panessa, Stefano Bianchi, Fabio La Franca, Nicolas Scepi, Mitchell C. Begelman, Anna Lia Longinotti, Elisabeta Lusso, Samantha Oates, Matt Nicholl, S. Bradley Cenko, Brendan O’Connor, Erica Hammerstein, Jincen Jose, Krisztina Éva Gabányi, Federica Ricci, and Sabyasachi Chattopadhyay

Subjects
Active galactic nuclei, X-ray active galactic nuclei, Seyfert galaxies, Astrophysics, QB460-466
Abstract

1ES1927+654 is a nearby active galactic nucleus (AGN) that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability patterns at timescales of months to years. Here we report the unusual X-ray, UV, and radio variability of the source in its postflare state (2022 January–2023 May). First, we detect an increase in the soft X-ray (0.3–2 keV) flux from 2022 May to 2023 May by almost a factor of 5, which we call the bright soft state. The hard X-ray 2–10 keV flux increased by a factor of 2, while the UV flux density did not show any significant changes (≤30%) in the same period. The integrated energy pumped into the soft and hard X-rays during this period of 11 months is ∼3.57 × 10 ^50 erg and 5.9 × 10 ^49 erg, respectively. From the energetics, it is evident that whatever is producing the soft excess (SE) is pumping out more energy than either the UV or hard X-ray source. Since the energy source presumably is ultimately the accretion of matter onto the supermassive black hole, the SE-emitting region must be receiving the majority of this energy. In addition, the source does not follow the typical disk–corona relation found in AGNs, neither in the initial flare (from 2017 to 2019) nor in the current bright soft state (2022–2023). We found that the core (

Published
2023
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4. Broad Band Observations of Gravitationally Lensed Blazar during a Gamma-Ray Outburst

Author

Julian Sitarek, Josefa Becerra González, Sara Buson, Dijana Dominis Prester, Marina Manganaro, Daniel Mazin, Kari Nilsson, Mireia Nievas, Antonio Stamerra, Fabrizio Tavecchio, and Ievgen Vovk

Subjects
gamma rays: galaxies, gravitational lensing: strong, galaxies: jets, radiation mechanisms: non-thermal, galaxies: QSO B0218+357, Astronomy, QB1-991
Abstract

QSO B0218+357 is a gravitationally lensed blazar located at a cosmological redshift of 0.944. In July 2014 a GeV flare was observed by Fermi-LAT, triggering follow-up observations with the MAGIC telescopes at energies above 100 GeV. The MAGIC observations at the expected time of arrival of the trailing component resulted in the first detection of QSO B0218+357 in Very-High-Energy (VHE, >100 GeV) gamma rays. We report here the observed multiwavelength emission during the 2014 flare.

Published
2016
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5. Simultaneous view of the FRB~180301 with FAST and NICER during a bursting phase

Author

Sibasish Laha, George Younes, Zorawar Wadiasingh, Bo-Jun Wang, Ke-Jia Lee, Noel Klingler, Bing Zhang, Heng Xu, Chun-Feng Zhang, Wei-Wei Zhu, Ritesh Ghosh, Amy Lien, Eleonora Troja, S. Bradley Cenko, Samantha Oates, Matt Nicholl, Josefa Becerra González, Eileen Meyer, and Tyler Parsotan

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

FRB180301 is one of the most actively repeating fast radio bursts (FRBs) which has shown polarization angle changes in its radio burst emission, an indication for their likely origin in the magnetosphere of a highly-magnetized neutron star. We carried out a multi-wavelength campaign with the FAST radio telescope and NICER X-ray observatory to investigate any possible X-ray emission temporally coincident with the bright radio bursts. The observations took place on 2021 March 4, 9 and 19. We detected five bright radio bursts with FAST, four of which were strictly simultaneous with the NICER observations. The peak flux-density of the radio bursts ranged between $28-105$ mJy, the burst fluence between $27-170$ mJy-ms, and the burst durations between $1.7-12.3$ ms. The radio bursts from FRB~180301 exhibited complex time domain structure, and sub-pulses were detected in individual bursts, with no significant circular polarisation. The linear degree of polarisation in L-band reduced significantly compared to the 2019 observations. We do not detect any X-ray emission in excess of the background during the 5ms, 10ms, 100ms, 1sec and 100sec time intervals at/around the radio-burst barycenter-corrected arrival times, at a $>5\sigma$ confidence level. The $5\sigma$ upper limits on the X-ray a) persistent flux is $, Comment: Resubmitted to ApJ following referee's minor comments

Published
2022

6. Search for Gamma-ray Line emission from Dark Matter annihilation in the Galactic Centre with the MAGIC telescopes

Author

Tomohiro Inada, Ana Babic, Andrés Baquero, Ivana Batković, Josefa Becerra Gonzalez, Jürgen Besenrieder, Hendrik Bökenkamp, Zeljka Bosnjak, Elia Do Souto Espiñeira, Ramon J. García López, Nikola Godinovic, Moritz Hütten, Irene Jiménez Martínez, Ruben Lopez-Coto, Marcos López-Moya, Alicia López-Oramas, Mosè Mariotti, Manel Martinez, Saša Mićanović, Lovro Pavletić, Pablo Peñil, Marc Ribó, Iva Šnidarić, Jelena Strišković, Tihomir Surić, Tomislav Terzic, Darko Zarić, Victor A. Acciari, Stefano Ansoldi, Lucio Angelo Antonelli, Axel Arbet Engels, Manuel Artero, Katsuaki Asano, Dominik Baack, Ana Babić, Ulisses Barres de Almeida, Juan Abel Barrio, Josefa Becerra González, Wlodek Bednarek, Lorenzo Bellizzi, Elisa Bernardini, Maria-Isabel Bernardos, Alessio Berti, Wrijupan Bhattacharyya, Ciro Bigongiari, Adrian Biland, Oscar Blanch, Giacomo Bonnoli, Željka Bošnjak, Giovanni Busetto, Roberto Carosi, Giovanni Ceribella, Matteo Cerruti, Yating Chai, Ashot Agassi Chilingarian, Stefan Cikota, Sidika Merve Colak, Eduardo Colombo, Jose Luis Contreras, Juan Cortina, Stefano Covino, Giacomo D'Amico, Valerio D'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, 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, Markus Garczarczyk, Sargis Gasparyan, Markus Gaug, Nicola Giglietto, Francesco Giordano, Pawel Gliwny, Nikola Godinović, David Green, Jarred Gershon Green, Daniela Hadasch, Alexander Hahn, Lea Heckmann, Javier Herrera, John Hoang, Dario Hrupec, Kazuma Ishio, Yuki Iwamura, Irene Jimenez-Martinez, Jenni Jormanainen, Léa 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, Rubén López-Coto, Serena Loporchio, Bernardo Machado de Oliveira Fraga, Camilla Maggio, Pratik Majumdar, Martin MAKARIEV, Manuela Mallamaci, Galina Maneva, Marina Manganaro, Karl Mannheim, Laura Maraschi, Manel Martínez, Daniel Mazin, Stefano Menchiari, Simone Mender, 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, Josep M. Paredes, Massimo Persic, Marine Pihet, Pier Giorgio Prada Moroni, Elisa Prandini, Chaitanya Priyadarshi, Ivica Puljak, Wolfgang Rhode, 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, Dorota Sobczyńska, Alessia Spolon, Antonio Stamerra, Derek Strom, Marcel C. Strzys, Yusuke Suda, Mitsunari Takahashi, Ryuji Takeishi, Fabrizio Tavecchio, Petar Temnikov, Tomislav Terzić, 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, and Daniele Ninci

Subjects
Physics, Annihilation, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Dark matter, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy, Spectral line, Sky, MAGIC (telescope), Zenith, Astrophysics::Galaxy Astrophysics, media_common
Abstract

We present the first search for dark matter (DM) spectral lines in the Galactic centre (GC) region with the MAGIC telescopes. The MAGIC telescopes, located on the Canary island of La Palma (Spain), are sensitive to gamma rays in the energy range from 50 GeV to 50 TeV. MAGIC has performed indirect DM searches in various astrophysical targets, such as dwarf spheroidal galaxies and clusters of galaxies. Observations at high zenith angles significantly increase the telescopes' collection area and sensitivity for gamma rays in the TeV regime. We present the results obtained with more than 200 hours of high-zenith angle observations of the GC region with MAGIC, which allow us to probe promising heavy SUSY models, and to obtain competitive limits to the DM annihilation cross-section at high DM particle mass, compared to existing constraints. We will discuss how we exploit the data from a complex sky region to search for a line-like DM signature., PoS: Proceedings of Science, 395, ISSN:1824-8039, 37th International Cosmic Ray Conference (ICRC 2021)

Published
2022
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7. CONSTRAINTS ON THE VERY HIGH ENERGY GAMMA-RAY EMISSION WITH HAWC

Author

Yunior Frainen Pérez, Maria Magdalena González, Nissim Illich Fraija, Anushka Udara Abeysekara, Andrea Albert, Ruben Alfaro, César Alvarez, Juan de Dios Álvarez Romero, José Roberto Angeles Camacho, Juan Carlos Arteaga Velazquez, Arun Babu Kollamparambil, Daniel Omar Avila Rojas, Hugo Alberto Ayala Solares, Rishi Babu, Vardan Baghmanyan, Ahron S. Barber, Josefa Becerra González, Ernesto Belmont-Moreno, Segev BenZvi, David Berley, Chad Brisbois, Karen S. Caballero Mora, Tomás Capistrán Rojas, Alberto Carramiñana, Sabrina Casanova, Oscar Chaparro-Amaro, Umberto Cotti, Jorge Cotzomi, Sara Coutiño de León, Eduardo de la Fuente, Cederik León de León, Lorenzo Diaz, Raquel Diaz Hernandez, Juan Carlos Díaz Vélez, Brenda Dingus, Mora Durocher, Michael DuVernois, Robert Ellsworth, Kristi Engel, María Catalina Espinoza Hernández, Jason Fan, Ke Fang, Mateo Fernandez Alonso, Brian Fick, Henrike Fleischhack, Jorge Luis Flores, Diego Garcia Aguilar, Jose Andres Garcia-Gonzalez, Jose Luis García-Luna, Guillermo García-Torales, Fernando Garfias, Gwenael Giacinti, Hazal Goksu, Jordan A. Goodman, J. Patrick Harding, Sergio Hernández Cadena, Ian Herzog, Jim Hinton, Binita Hona, Dezhi Huang, Filiberto Hueyotl-Zahuantitla, Michelle Hui, Brian Humensky, Petra Hüntemeyer, Arturo Iriarte, Armelle Jardin-Blicq, Hannah Jhee, Vikas Joshi, David Kieda, Gerd J. Kunde, Samridha Kunwar, Alejandro Lara, Jason LEE, William H. Lee, Dirk Lennarz, Hermes Leon Vargas, Jim Linnemann, Anna Lia Longinotti, Rubén López-Coto, Gilgamesh Luis-Raya, Joe Lundeen, Kelly Malone, Vincent Marandon, Oscar M Martinez, Israel Martinez Castellanos, Humberto Martínez Huerta, Jesús Martínez-Castro, John Matthews, Julie McEnery, Pedro Miranda-Romagnoli, Jorge Antonio Morales Soto, Eduardo Moreno Barbosa, Miguel Mostafa, Amid Nayerhoda, Lukas Nellen, Michael Newbold, Mehr Un Nisa, Roberto Noriega-Papaqui, Laura Olivera-Nieto, Nicola Omodei, Alison Peisker, Eucario Gonzalo Pérez Pérez, Chang Dong Rho, Colas Rivière, Daniel Rosa-Gonzalez, Edna Ruiz-Velasco, James Ryan, Humberto Ibarguen Salazar, Francisco Salesa Greus, Andrés Sandoval, Michael Schneider, Harm Schoorlemmer, José Serna-Franco, Gus Sinnis, Andrew James Smith, Wayne Robert Springer, Pooja Surajbali, Ignacio Taboada, Meghan Tanner, Kirsten Tollefson, Ibrahim Torres, Ramiro Torres Escobedo, Rhiannon M. Turner, Fernando Josue Urena Mena, Luis Villaseñor, Xiaojie Wang, Ian James Watson, Thomas Weisgarber, Felix Werner, Elijah Job Willox, Joshua Wood, Gaurang Yodh, Arnulfo Zepeda, and Hao Zhou

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, High energy, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Phase (waves), FOS: Physical sciences, Context (language use), Astrophysics, Parameter space, Light curve, Synchrotron, law.invention, Afterglow, law, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Gamma-ray bursts (GRBs) are among the most luminous sources in the universe. The nature of their emission at TeV energies is one of the most relevant open issues related to these events. The temporal and spectral features inferred from the early and late emissions usually known as prompt and afterglow, respectively, can be interpreted within the context of the fireball model. The synchrotron self-Compton process is expected during the afterglow phase. We explain how the theoretical SSC light curves can be compared with hypothetical upper limit located at z=0.3. We show the allowed parameter space of the microphysical parameters and density of the circumburst medium. The most restrictive results are obtained when the SSC process lies in the fast cooling regime, Comment: Presented at the 37th International Cosmic Ray Conference(ICRC2021),Berlin, Germany-online

Published
2021
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8. Follow-up observations of GW170817 with the MAGIC telescopes

Author

Antonio Stamerra, Om Sharan Salafia, Alessio Berti, Stefano Covino, Valerio D'Elia, Davide Miceli, Lara Nava, Barbara Patricelli, Chiara Righi, Susumu Inoue, Lucio Angelo Antonelli, Stefano Ansoldi, Barbara De Lotto, Francesco Longo, Fabrizio Tavecchio, Ana Babic, Josefa Becerra Gonzalez, Zeljka Bosnjak, Nikola Godinovic, Ruben Lopez-Coto, Manel Martinez, Tomislav Terzic, Victor A. Acciari, Axel Arbet Engels, Manuel Artero, Katsuaki Asano, Dominik Baack, Ana Babić, Andrés Baquero, Ulisses Barres de Almeida, Juan Abel Barrio, Ivana Batković, Josefa Becerra González, Wlodek Bednarek, Lorenzo Bellizzi, Elisa Bernardini, Maria-Isabel Bernardos, Jürgen Besenrieder, Wrijupan Bhattacharyya, Ciro Bigongiari, Adrian Biland, Oscar Blanch, Hendrik Bökenkamp, Giacomo Bonnoli, Željka Bošnjak, Giovanni Busetto, Roberto Carosi, Giovanni Ceribella, Matteo Cerruti, Yating Chai, Ashot Agassi Chilingarian, Stefan Cikota, Sidika Merve Colak, Eduardo Colombo, Jose Luis Contreras, Juan Cortina, Giacomo D'Amico, Paolo Da Vela, Francesco Dazzi, Alessandro De Angelis, Manuel Delfino, Jordi Delgado, Carlos Delgado Mendez, Davide Depaoli, Federico Di Pierro, Leonardo Di Venere, Elia Do Souto Espiñeira, 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, Ramon J. García López, Markus Garczarczyk, Sargis Gasparyan, Markus Gaug, Nicola Giglietto, Francesco Giordano, Pawel Gliwny, Nikola Godinović, David Green, Jarred Gershon Green, Daniela Hadasch, Alexander Hahn, Lea Heckmann, Javier Herrera, John Hoang, Dario Hrupec, Moritz Hütten, Tomohiro Inada, Kazuma Ishio, Yuki Iwamura, Irene Jiménez Martínez, Jenni Jormanainen, Léa Jouvin, Marie Karjalainen, Daniel Kerszberg, Yukiho Kobayashi, Hidetoshi Kubo, Junko Kushida, Alessandra Lamastra, Damir LELAS, Francesco Leone, Elina Lindfors, Lena Linhoff, Saverio Lombardi, Rubén López-Coto, Marcos López-Moya, Alicia López-Oramas, Serena Loporchio, Bernardo Machado de Oliveira Fraga, Camilla Maggio, Pratik Majumdar, Martin MAKARIEV, Manuela Mallamaci, Galina Maneva, Marina Manganaro, Karl Mannheim, Laura Maraschi, Mosè Mariotti, Manel Martínez, Daniel Mazin, Stefano Menchiari, Simone Mender, Saša Mićanović, Tjark Miener, Jose Miguel Miranda, Razmik Mirzoyan, Edgar Molina, Abelardo Moralejo, Daniel Morcuende, Victoria Moreno, Elena Moretti, Takeshi Nakamori, 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, Josep M. Paredes, Lovro Pavletić, Pablo Peñil, Massimo Persic, Marine Pihet, Pier Giorgio Prada Moroni, Elisa Prandini, Chaitanya Priyadarshi, Ivica Puljak, Wolfgang Rhode, Marc Ribó, Javier Rico, Andrea Rugliancich, Narek Sahakyan, Takayuki Saito, Shunsuke Sakurai, Konstancja Satalecka, Francesco Gabriele Saturni, Bernd Schleicher, Kevin Schmidt, Thomas Schweizer, Julian Sitarek, Iva Šnidarić, Dorota Sobczyńska, Alessia Spolon, Jelena Strišković, Derek Strom, Marcel C. Strzys, Yusuke Suda, Tihomir Surić, Mitsunari Takahashi, Ryuji Takeishi, Petar Temnikov, Tomislav Terzić, 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, and Darko Zarić

Subjects
Physics, Neutron star, Gravitational wave, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, MAGIC (telescope), Maximum flux, Gamma-ray burst
Abstract

The discovery of the electromagnetic counterpart AT2017gfo and the GRB 170817A, associated to the binary neutron star merger GW170817, was one of the major advances in the study of gamma- ray bursts (GRBs) and the hallmark of the multi-messenger astronomy with gravitational waves. Another breakthrough in GRB physics is represented by the discovery of the highly energetic, teraelectronvolt (TeV) component in the GRB 190114C, possibly an universal component in all GRBs. This conclusion is also suggested by the hint of TeV emission in the short GRB 160821B and a few more events reported in the literature. The missing observational piece is the joint detection of TeV emission and gravitational waves from a short GRB and its progenitor. MAGIC observed the counterpart AT2017gfo as soon as the visibility conditions allowed it, namely from January to June 2018. These observations correspond to the maximum flux level observed in the radio and X-ray bands. The upper limits derived from TeV observations are compared with the modelling of the late non-thermal emission using the multi-frequency SED.

Published
2021
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9. Limits on the Hard X-Ray Emission From the Periodic Fast Radio Burst FRB 180916.J0158+65

Author

Sibasish Laha, Zorawar Wadiasingh, Tyler Parsotan, Amy Lien, George Younes, Bing Zhang, S. Bradley Cenko, Eleonora Troja, Samantha Oates, Matt Nicholl, Eileen Meyer, Josefa Becerra González, Ritesh Ghosh, and Noel Klingler

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

FRB 180916.J0158+65 is one of the nearest, periodically repeating, and actively bursting fast radio burst (FRB) which has been localized to the outskirts of a spiral galaxy. In this work we study the FRB with the hard X-ray $14-195$ keV data from the Burst Alert Telescope (BAT) on board The Neil Gehrels Swift Observatory. BAT uses coded mask technology giving a localization of $\lesssim 3$ arc-minute in the hard X-ray band, along with an accurate background estimation. BAT has been observing the source location in survey mode since February 2020. The survey mode observations involves background subtracted spectra, integrated over a time span ranging $300-2000$ seconds, at the source location (from Feb 2020-Jan 2022). We analyzed all the $\sim 230$ survey mode observations from BAT and checked for any signal in any of the observations. We did not detect any signal at $>5\sigma$ confidence level in any of the observations. We could estimate a $5\sigma$ upper limit on the $14-195$ keV flux, which ranged between $4.5\times 10^{-10} - 7.6\times 10^{-9}\, \rm erg\, cm^{-2}\, s^{-1}$. At the source distance this relates to a $5\sigma$ upper limit on luminosity of $5.08\times 10^{44}- 8.5\times 10^{45} \rm erg\, s^{-1}$. With this estimate, we could rule out any persistent X-ray emission, at the source location for these snapshots of BAT observations., Comment: Accepted for publication in ApJ

Published
2022
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10. VHE BL Lacs through the MAGIC glasses

Author

Josefa Becerra González

Subjects
Physics, Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, MAGIC (telescope), BL Lac object
Abstract

In this contribution an overview of the latest results on the study of BL Lac objects with the MAGIC telescopes at the very high energy (VHE, E>100 GeV) gamma-rays is presented. Three new VHE sources were detected during 2014, two BL Lac objects and the gravitational lensed blazar S3 0218+357. MAGIC detected very fast intra-night variability from IC 310. This detection points to smaller emitting regions than the event horizon, this is hard to be explained in the framework of the current theoretical models. The long term multi wavelength (MWL) study of the BL Lac PKS 1424+240 shows correlation between the radio and optical emission, pointing to a common origin. The MWL SED is not well fitted by a one-zone synchrotron-self Compton (SSC) model, but a two-zone SSC model can explain both, the MWL light curve and the SED. Spectral curvature has been found in the observed VHE spectrum from PG 1553+113. This is the first time that spectral curvature compatible with the EBL absorption is found in an individual object.

Published
2014
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11. Synoptics study of blazars detected at very high energy gamma-rays

Author

Josefa Becerra González, Martin Raue, and Robert Wagner

Subjects
Physics, Active galactic nucleus, Line-of-sight, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma ray, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Cherenkov Telescope Array, Wavelength, Sky, Blazar, Astrophysics::Galaxy Astrophysics, Cherenkov radiation, media_common
Abstract

Due to the increased sensitivity of the present generation of Cherenkov telescopes, the knowledge of the Very High Energy (VHE, E>100 GeV) gamma-ray sky has substantially increased in the past years. In particular, in the extragalactic sky a wealth of new sources and source classes has been discovered. Today, more than 50 extragalactic sources have been detected, 45 of them being Blazars, i.e., Active Galactic Nuclei (AGNs) with their jet aligned close to the line of sight to the observer. A population study of them is being carried out investigating the correlation among different physical parameters inherent to the VHE measurements as well parameters coming from other wavelengths, extending beyond quantities strictly related to the emission characteristics of the blazar (e.g. BH mass). In this contribution, preliminary results from the population study are presented. This study is particularly interesting for the future perspective of present generation of Cherenkov telescopes as well as for the future Cherenkov Telescope Array (CTA) in order to identify the characteristics of the sources which are likely to be detected at such energy range.

Published
2012
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