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9 results on '"J. Jormanainen"'

1. Multimessenger Characterization of Markarian 501 during Historically Low X-Ray and γ-Ray Activity

Author

H. Abe, S. Abe, V. A. Acciari, I. Agudo, T. Aniello, S. Ansoldi, L. A. Antonelli, A. Arbet-Engels, C. Arcaro, M. Artero, K. Asano, D. Baack, A. Babić, A. Baquero, U. Barres de Almeida, J. A. Barrio, I. Batković, J. Baxter, J. Becerra González, W. Bednarek, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Ž. Bošnjak, I. Burelli, G. Busetto, R. Carosi, M. Carretero-Castrillo, A. J. Castro-Tirado, G. Ceribella, Y. Chai, A. Chilingarian, S. Cikota, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, A. Del Popolo, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, F. Di Pierro, L. Di Venere, E. Do Souto Espiñeira, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, G. Emery, J. Escudero, V. Fallah Ramazani, L. Fariña, A. Fattorini, L. Foffano, L. Font, C. Fruck, S. Fukami, Y. Fukazawa, R. J. García López, M. Garczarczyk, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, R. Grau, D. Green, J. G. Green, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera, D. Hrupec, M. Hütten, R. Imazawa, T. Inada, R. Iotov, K. Ishio, I. Jiménez Martínez, J. Jormanainen, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, L. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, E. Lyard, B. Machado de Oliveira Fraga, P. Majumdar, M. Makariev, G. Maneva, N. Mang, M. Manganaro, S. Mangano, K. Mannheim, M. Mariotti, M. Martínez, A. Mas-Aguilar, D. Mazin, S. Menchiari, S. Mender, S. Mićanović, D. Miceli, T. Miener, J. M. Miranda, R. Mirzoyan, E. Molina, H. A. Mondal, A. Moralejo, D. Morcuende, V. Moreno, T. Nakamori, C. Nanci, L. Nava, V. Neustroev, M. Nievas Rosillo, C. Nigro, K. Nilsson, K. Nishijima, T. Njoh Ekoume, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, A. Okumura, J. Otero-Santos, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletić, M. Persic, M. Pihet, G. Pirola, F. Podobnik, P. G. Prada Moroni, E. Prandini, G. Principe, C. Priyadarshi, W. Rhode, M. Ribó, J. Rico, C. Righi, A. Rugliancich, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, F. G. Saturni, B. Schleicher, K. Schmidt, F. Schmuckermaier, J. L. Schubert, T. Schweizer, J. Sitarek, V. Sliusar, D. Sobczynska, A. Spolon, A. Stamerra, J. Strišković, D. Strom, M. Strzys, Y. Suda, T. Surić, H. Tajima, M. Takahashi, R. Takeishi, F. Tavecchio, P. Temnikov, K. Terauchi, T. Terzić, M. Teshima, L. Tosti, S. Truzzi, A. Tutone, S. Ubach, J. van Scherpenberg, M. Vazquez Acosta, S. Ventura, V. Verguilov, I. Viale, C. F. Vigorito, V. Vitale, I. Vovk, R. Walter, M. Will, C. Wunderlich, T. Yamamoto, D. Zarić, The MAGIC Collaboration, M. Cerruti, J. A. Acosta-Pulido, G. Apolonio, R. Bachev, M. Baloković, E. Benítez, I. Björklund, V. Bozhilov, L. F. Brown, A. Bugg, W. Carbonell, M. I. Carnerero, D. Carosati, C. Casadio, W. Chamani, W. P. Chen, R. A. Chigladze, G. Damljanovic, K. Epps, A. Erkenov, M. Feige, J. Finke, A. Fuentes, K. Gazeas, M. Giroletti, T. S. Grishina, A. C. Gupta, M. A. Gurwell,, E. Heidemann, D. Hiriart, W. J. Hou, T. Hovatta, S. Ibryamov, M. D. Joner, S. G. Jorstad, J. Kania, S. Kiehlmann, G. N. Kimeridze, E. N. Kopatskaya, M. Kopp, M. Korte, B. Kotas, S. Koyama, J. A. Kramer, L. Kunkel, S. O. Kurtanidze, O. M. Kurtanidze, A. Lähteenmäki, J. M. López, V. M. Larionov, E. G. Larionova, L. V. Larionova, C. Leto, C. Lorey, R. Mújica, G. M. Madejski, N. Marchili, A. P. Marscher, M. Minev, A. Modaressi, D. A. Morozova, T. Mufakharov, I. Myserlis, A. A. Nikiforova, M. G. Nikolashvili, E. Ovcharov, M. Perri, C. M. Raiteri, A. C. S. Readhead, A. Reimer, D. Reinhart, S. Righini, K. Rosenlehner, A. C. Sadun, S. S. Savchenko, A. Scherbantin, L. Schneider, K. Schoch, D. Seifert, E. Semkov, L. A. Sigua, C. Singh, P. Sola, Y. Sotnikova, M. Spencer, R. Steineke, M. Stojanovic, A. Strigachev, M. Tornikoski, E. Traianou, A. Tramacere, Yu. V. Troitskaya, I. S. Troitskiy, J. B. Trump, A. Tsai, A. Valcheva, A. A. Vasilyev, F. Verrecchia, M. Villata, O. Vince, K. Vrontaki, Z. R. Weaver, E. Zaharieva, and N. Zottmann

Subjects
Active galaxies, BL Lacertae objects, Markarian galaxies, Active galactic nuclei, Blazars, Astrophysics, QB460-466
Abstract

We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) γ -rays. A significant correlation (>3 σ ) between X-rays and VHE γ -rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy γ -rays and radio, with the radio lagging by more than 100 days, placing the γ -ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE γ -rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2 TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2 yr long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock.

Published
2023
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2. Multiwavelength study of the gravitationally lensed blazar QSO B0218+357 between 2016 and 2020

Author

V A Acciari, S Ansoldi, L A Antonelli, A Arbet Engels, M Artero, K Asano, D Baack, A Babić, A Baquero, U Barres de Almeida, J A Barrio, I Batković, J Becerra González, W Bednarek, L Bellizzi, E Bernardini, M Bernardos, A Berti, J Besenrieder, W Bhattacharyya, C Bigongiari, A Biland, O Blanch, G Bonnoli, Ž Bošnjak, G Busetto, R Carosi, G Ceribella, M Cerruti, Y Chai, A Chilingarian, S Cikota, S M Colak, E Colombo, J L Contreras, J Cortina, S Covino, G D’Amico, V D’Elia, P Da Vela, F Dazzi, A De Angelis, B De Lotto, M Delfino, J Delgado, C Delgado Mendez, D Depaoli, F Di Pierro, L Di Venere, E Do Souto Espiñeira, D Dominis Prester, A Donini, D Dorner, M Doro, D Elsaesser, V Fallah Ramazani, A Fattorini, G Ferrara, M V Fonseca, L Font, C Fruck, S Fukami, R J García López, M Garczarczyk, S Gasparyan, M Gaug, N Giglietto, F Giordano, P Gliwny, N Godinović, J G Green, D Green, D Hadasch, A Hahn, L Heckmann, J Herrera, J Hoang, D Hrupec, M Hütten, T Inada, S Inoue, K Ishio, Y Iwamura, I Jiménez, J Jormanainen, L Jouvin, Y Kajiwara, M Karjalainen, D Kerszberg, Y Kobayashi, H Kubo, J Kushida, A Lamastra, D Lelas, F Leone, E Lindfors, S Lombardi, F Longo, R López-Coto, M López-Moya, A López-Oramas, S Loporchio, B Machado de Oliveira Fraga, C Maggio, P Majumdar, M Makariev, M Mallamaci, G Maneva, M Manganaro, K Mannheim, L Maraschi, M Mariotti, M Martínez, D Mazin, S Menchiari, S Mender, S Mićanović, D Miceli, T Miener, M Minev, J M Miranda, R Mirzoyan, E Molina, A Moralejo, D Morcuende, V Moreno, E Moretti, V Neustroev, C Nigro, K Nilsson, K Nishijima, K Noda, S Nozaki, Y Ohtani, T Oka, J Otero-Santos, S Paiano, M Palatiello, D Paneque, R Paoletti, J M Paredes, L Pavletić, P Peñil, C Perennes, M Persic, P G Prada Moroni, E Prandini, C Priyadarshi, I Puljak, W Rhode, M Ribó, J Rico, C Righi, A Rugliancich, L Saha, N Sahakyan, T Saito, S Sakurai, K Satalecka, F G Saturni, B Schleicher, K Schmidt, T Schweizer, J Sitarek, I Šnidarić, D Sobczynska, A Spolon, A Stamerra, D Strom, M Strzys, Y Suda, T Surić, M Takahashi, F Tavecchio, P Temnikov, T Terzić, M Teshima, L Tosti, S Truzzi, A Tutone, S Ubach, J van Scherpenberg, G Vanzo, M Vazquez Acosta, S Ventura, V Verguilov, C F Vigorito, V Vitale, I Vovk, M Will, C Wunderlich, D Zarić, F de Palma, F D’Ammando, A Barnacka, D K Sahu, M Hodges, T Hovatta, S Kiehlmann, W Max-Moerbeck, A C S Readhead, R Reeves, T J Pearson, A Lähteenmäki, I Björklund, M Tornikoski, J Tammi, S Suutarinen, K Hada, and K Niinuma

Published
2021
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3. Multiwavelength Variability and Correlation Studies of Mrk 421 During Historically Low X-ray and Y-ray Activity in 2015–2016

Author

Janeth Valverde Quispe, V. A. Acciari, S. Ansoldi, L. A. Antonelli, K. Asano, A. Babic, B. Banerjee, A. Baquero, U.BarresdeAlmeida, J. A. Barrio, J. Becerra Gonzalez, W. Bednarek, L. Bellizzi, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, O. Blanch, G. Bonnoli, Z. Bosnjak, G. Busetto, R. Carosi, G. Ceribella, M. Cerruti, Y. Chai, A. Chilingarian, S. Cikota, S. M. Colak, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, T. Di Girolamo, F. Di Pierro, L. Di Venere, E. Do Souto Espineira, D. Dominis Prester, A. Donini, M. Doro, V. Fallah Ramazani, A. Fattorini, G. Ferrara, L. Foffano, M. V. Fonseca, L. Font, C. Fruck, S. Fukami, R. J. Garcıa Lopez, M. Garczarczyk, S. Gasparyan, M. Gaug, N. Giglietto, F. Giordano, P. Gliwny, N. Godinovic, J. G. Green, D. Green, D. Hadasch, A. Hahn, L. Heckmann, J. Herrera, J. Hoang, D. Hrupec, M. Hutten, T. Inada, S. Inoue, K. Ishio, Y. Iwamura, J. Jormanainen, L. Jouvin, Y. Kajiwara, M. Karjalainen, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, S. Lombardi, F. Longo, M. Lopez, R. Lopez-Coto, A. Lopez-Oramas, S. Loporchio, B. Machado de Oliveira Fraga, C. Maggio, P. Majumdar, M. Makariev, M. Mallamaci, G. Maneva, M. Manganaro, L. Maraschi, M. Mariotti, M. Martınez, D. Mazin, S. Mender, S. Micanovic, D. Miceli, T. Miener, M. Minev, J. M. Miranda, R. Mirzoyan, E. Molina, A. Moralejo, D. Morcuende, V. Moreno, E. Moretti, P. Munar-Adrover, V. Neustroev, C. Nigro, K. Nilsson, D. Ninci, K. Nishijima, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, J. Otero-Santos, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletic, P. P enil, C. Perennes, M. Persic, P. G . Prada Moroni, E. Prandini, C. Priyadarshi, I. Puljak, W. Rhode, M. Ribo, J. Rico, C. Righi, A. Rugliancich, L. Saha, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, B. Schleicher, K. Schmidt, T. Schweizer, J. Sitarek, I. Snidaric, D. Sobczynska, A. Spolon, A. Stamerra, D. Strom, M. Strzys, Y. Suda, T. Suric, M. Takahashi, F. Tavecchio, P. Temnikov, T. Terzic, M. Teshima, N. Torres-Alba, L. Tosti, S. Truzzi, J. van Scherpenberg, G. Vanzo, M. Vazquez Acosta, S. Ventura, V. Verguilov, C. F. Vigorito, V. Vitale, I. Vovk, M. Will, D. Zaric, A. Arbet-Engels, D. Baack, M. Balbo, M. Beck, N. Biederbeck, A. Biland, T. Bretz, K. Bruegge, J. Buss, D. Dorner, D. Elsaesser, D. Hildebrand, R. Iotov, M. Klinger, K. Mannheim, D. Neise, A. Neronov, M. Noethe, A. Paravac, V. Sliusar, F. Theissen, R. Walter, J. Valverde, D. Horan, M. Giroletti, M. Perri, F. Verrecchia, C. Leto, A. C. Sadun, J. W. Moody, M. Joner, A. P. Marscher, S. G. Jorstad, A. Lahteenmaki, M. Tornikoski, V. Ramakrishnan, E. Jarvela, R. J. C. Vera, S. Righini, and A.Y.Lien

Subjects
Astronomy
Abstract

We report a characterization of the multiband flux variability and correlations of the nearby (z=0.031) blazar Markarian 421(Mrk 421) using data from Mets ̈ahovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F>1TeV<1.7×10−12ph cm−2s−1) and in the 2–10 keV (X-ray) band (F2−10 keV<3.6×10−11erg cm−2s−1),during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E>0.1 TeV)γ-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HRkeV and HRTeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our dataset with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of 43+9−6d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process.

Published
2020
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4. Optical polarization reveals colliding stellar stream shocks in a tidal disruption event

Author

I. Liodakis, K. I. I. Koljonen, D. Blinov, E. Lindfors, K. D. Alexander, T. Hovatta, M. Berton, A. Hajela, J. Jormanainen, K. Kouroumpatzakis, N. Mandarakas, and K. Nilsson

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

Supermassive black holes have been known to disrupt passing stars producing outbursts called Tidal Disruption Events offering a unique view on the early stages of accretion disk and jet formation. The advent of large scale optical time-domain surveys has significantly increased the number of known events and challenged our understanding of their dynamics and emission processes. Here, we present the linear polarization curve of the most polarized tidal disruption without any indication of contribution from a jet to the emission. Our observations demonstrate that optical TDE emission can be powered by tidal stream shocks., Comment: 36 pages, 7 figures, author's version of the paper accepted in Science

Published
2022
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5. Aluminium corrosion in power semiconductor devices

Author

J. Leppänen, J. Ingman, J.-H. Peters, M. Hanf, R. Ross, G. Koopmans, J. Jormanainen, A. Forsström, G. Ross, N. Kaminski, V. Vuorinen, Department of Electrical Engineering and Automation, ABB Oy Drives, University of Bremen, IWO Ede NL, Department of Bioproducts and Biosystems, Aalto-yliopisto, and Aalto University

Subjects
ECM, Aluminium corrosion, LiT, Pourbaix diagram, Condensed Matter Physics, IGBT, Atomic and Molecular Physics, and Optics, MIP, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, FIB, PoF, Electrical and Electronic Engineering, Safety, Risk, Reliability and Quality, EoL, HV-HTRB
Abstract

Funding Information: The work presented in this publication has been carried out by an international research consortium at ABB Drives in Finland, at Aalto University (at Micronova and Nano Microscopy Center) in Finland, at University of Bremen in Germany, and at IWO Ede NL in the Netherlands. We extend special thanks to Jiaco Instruments for the support given by their demonstration of their MIP decapsulation technique which was used for the samples used in this article. We also extend our thanks to Fraunhofer IMWS in Germany for special permission to trial LiT equipment on one of the samples described in this work. The work has been partially funded by the Power2Power project , which is a co-funded European innovation project in the semiconductor industry. The project receives grants from the European H2020 research and innovation programme , the ECSEL Joint Undertaking and national funding authorities from the eight involved countries under grant agreement No 826417 . The participating countries are Austria, Finland, Germany (including the free states of Saxony and Thuringia), Hungary, the Netherlands, Slovakia, Spain and Switzerland. Funding Information: The work presented in this publication has been carried out by an international research consortium at ABB Drives in Finland, at Aalto University (at Micronova and Nano Microscopy Center) in Finland, at University of Bremen in Germany, and at IWO Ede NL in the Netherlands. We extend special thanks to Jiaco Instruments for the support given by their demonstration of their MIP decapsulation technique which was used for the samples used in this article. We also extend our thanks to Fraunhofer IMWS in Germany for special permission to trial LiT equipment on one of the samples described in this work. The work has been partially funded by the Power2Power project, which is a co-funded European innovation project in the semiconductor industry. The project receives grants from the European H2020 research and innovation programme, the ECSEL Joint Undertaking and national funding authorities from the eight involved countries under grant agreement No 826417. The participating countries are Austria, Finland, Germany (including the free states of Saxony and Thuringia), Hungary, the Netherlands, Slovakia, Spain and Switzerland. Publisher Copyright: © 2022 The Author(s) | openaire: EC/H2020/826417/EU//Power2Power In this study, insulated gate bipolar transistor (IGBT) power modules were exposed to high voltage, high humidity, high temperature and reverse bias (HV-H3TRB) conditions until end-of-life (EoL). The limited lifetime of power semiconductor devices when used in demanding applications involving high relative humidity during operation is commonly reported to be associated with the design of the edge termination in power transistor or diode chips. A physics-of-failure (PoF) oriented methodology was adopted in failure analysis, including using lock-in thermography (LiT) for failure localisation and using an advanced microwave-induced plasma (MIP) decapsulation technique for the selective etching of the edge termination polyimide passivation film. A focused ion beam (FIB) was utilised to create a cross-section of the samples for both scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis. The evidence gathered using the physics-of-failure methodology were compared with the results from advanced statistical analysis of the failure distributions in Weibull plots, including comparison of α and β parameters. This analysis revealed correlation with the Weibull distributions and the results from the physics-of-failure. Aluminium corrosion products were systematically observed on guard rings (GR) and field plates (FP) showing that the migration of these corrosion products forming an electrical path between the guard rings that seems to be a major failure mechanism in high humidity environments when reverse bias voltage is applied.

Published
2022
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6. Author Correction: Proton acceleration in thermonuclear nova explosions revealed by gamma rays

Author

V. A. Acciari, S. Ansoldi, L. A. Antonelli, A. Arbet Engels, M. Artero, K. Asano, D. Baack, A. Babić, A. Baquero, U. Barres de Almeida, J. A. Barrio, I. Batković, J. Becerra González, W. Bednarek, L. Bellizzi, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, A. Biland, O. Blanch, H. Bökenkamp, G. Bonnoli, Ž. Bošnjak, G. Busetto, R. Carosi, G. Ceribella, M. Cerruti, Y. Chai, A. Chilingarian, S. Cikota, S. M. Colak, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, A. Del Popolo, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, F. Di Pierro, L. Di Venere, E. Do Souto Espiñeira, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, V. Fallah Ramazani, L. Fariña Alonso, A. Fattorini, M. V. Fonseca, L. Font, C. Fruck, S. Fukami, Y. Fukazawa, R. J. García López, M. Garczarczyk, S. Gasparyan, M. Gaug, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, J. G. Green, D. Green, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera, J. Hoang, D. Hrupec, M. Hütten, T. Inada, K. Ishio, Y. Iwamura, I. Jiménez Martínez, J. Jormanainen, L. Jouvin, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, L. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, B. Machado de Oliveira Fraga, C. Maggio, P. Majumdar, M. Makariev, M. Mallamaci, G. Maneva, M. Manganaro, K. Mannheim, L. Maraschi, M. Mariotti, M. Martínez, A. Mas Aguilar, D. Mazin, S. Menchiari, S. Mender, S. Mićanović, D. Miceli, T. Miener, J. M. Miranda, R. Mirzoyan, E. Molina, A. Moralejo, D. Morcuende, V. Moreno, E. Moretti, T. Nakamori, L. Nava, V. Neustroev, M. Nievas Rosillo, C. Nigro, K. Nilsson, K. Nishijima, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, J. Otero-Santos, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletić, P. Peñil, M. Persic, M. Pihet, P. G. Prada Moroni, E. Prandini, C. Priyadarshi, I. Puljak, W. Rhode, M. Ribó, J. Rico, C. Righi, A. Rugliancich, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, F. G. Saturni, B. Schleicher, K. Schmidt, T. Schweizer, J. Sitarek, I. Šnidarić, D. Sobczynska, A. Spolon, A. Stamerra, J. Strišković, D. Strom, M. Strzys, Y. Suda, T. Surić, M. Takahashi, R. Takeishi, F. Tavecchio, P. Temnikov, T. Terzić, M. Teshima, L. Tosti, S. Truzzi, A. Tutone, S. Ubach, J. van Scherpenberg, G. Vanzo, M. Vazquez Acosta, S. Ventura, V. Verguilov, C. F. Vigorito, V. Vitale, I. Vovk, M. Will, C. Wunderlich, T. Yamamoto, D. Zarić, F. Ambrosino, M. Cecconi, G. Catanzaro, C. Ferrara, A. Frasca, M. Munari, L. Giustolisi, J. Alonso-Santiago, M. Giarrusso, U. Munari, and P. Valisa

Subjects
Astronomy and Astrophysics
Published
2022
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7. Optical polarization from colliding stellar stream shocks in a tidal disruption event.

Author

Liodakis I, Koljonen KII, Blinov D, Lindfors E, Alexander KD, Hovatta T, Berton M, Hajela A, Jormanainen J, Kouroumpatzakis K, Mandarakas N, and Nilsson K

Abstract

A tidal disruption event (TDE) occurs when a supermassive black hole rips apart a passing star. Part of the stellar material falls toward the black hole, forming an accretion disk that in some cases launches a relativistic jet. We performed optical polarimetry observations of a TDE, AT 2020mot. We find a peak linear polarization degree of 25 ± 4%, consistent with highly polarized synchrotron radiation, as is typically observed from relativistic jets. However, our radio observations, taken up to 8 months after the optical peak, do not detect the corresponding radio emission expected from a relativistic jet. We suggest that the linearly polarized optical emission instead arises from shocks that occur during accretion disk formation, as the stream of stellar material collides with itself.

Published
2023
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8. Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC.

Author

Abe H, Abe S, Acciari VA, Aniello T, Ansoldi S, Antonelli LA, Arbet Engels A, Arcaro C, Artero M, Asano K, Baack D, Babić A, Baquero A, Barres de Almeida U, Barrio JA, Batković I, Baxter J, Becerra González J, Bednarek W, Bernardini E, Bernardos M, Berti A, Besenrieder J, Bhattacharyya W, Bigongiari C, Biland A, Blanch O, Bonnoli G, Bošnjak Ž, Burelli I, Busetto G, Carosi R, Carretero-Castrillo M, Ceribella G, Chai Y, Chilingarian A, Cikota S, Colombo E, Contreras JL, Cortina J, Covino S, D'Amico G, D'Elia V, Da Vela P, Dazzi F, De Angelis A, De Lotto B, Del Popolo A, Delfino M, Delgado J, Delgado Mendez C, Depaoli D, Di Pierro F, Di Venere L, Do Souto Espiñeira E, Dominis Prester D, Donini A, Dorner D, Doro M, Elsaesser D, Emery G, Fallah Ramazani V, Fariña L, Fattorini A, Font L, Fruck C, Fukami S, Fukazawa Y, García López RJ, Garczarczyk M, Gasparyan S, Gaug M, Giesbrecht Paiva JG, Giglietto N, Giordano F, Gliwny P, Godinović N, Green JG, Green D, Hadasch D, Hahn A, Hassan T, Heckmann L, Herrera J, Hrupec D, Hütten M, Imazawa R, Inada T, Iotov R, Ishio K, Jiménez Martínez I, Jormanainen J, Kerszberg D, Kobayashi Y, Kubo H, Kushida J, Lamastra A, Lelas D, Leone F, Lindfors E, Linhoff L, Lombardi S, Longo F, López-Coto R, López-Moya M, López-Oramas A, Loporchio S, Lorini A, Lyard E, Machado de Oliveira Fraga B, Majumdar P, Makariev M, Maneva G, Mang N, Manganaro M, Mangano S, Mannheim K, Mariotti M, Martínez M, Mas Aguilar A, Mazin D, Menchiari S, Mender S, Mićanović S, Miceli D, Miener T, Miranda JM, Mirzoyan R, Molina E, Mondal HA, Moralejo A, Morcuende D, Moreno V, Nakamori T, Nanci C, Nava L, Neustroev V, Nievas Rosillo M, Nigro C, Nilsson K, Nishijima K, Njoh Ekoume T, Noda K, Nozaki S, Ohtani Y, Oka T, Otero-Santos J, Paiano S, Palatiello M, Paneque D, Paoletti R, Paredes JM, Pavletić L, Persic M, Pihet M, Podobnik F, Prada Moroni PG, Prandini E, Principe G, Priyadarshi C, Puljak I, Rhode W, Ribó M, Rico J, Righi C, Rugliancich A, Sahakyan N, Saito T, Sakurai S, Satalecka K, Saturni FG, Schleicher B, Schmidt K, Schmuckermaier F, Schubert JL, Schweizer T, Sitarek J, Sliusar V, Sobczynska D, Spolon A, Stamerra A, Strišković J, Strom D, Strzys M, Suda Y, Surić T, Takahashi M, Takeishi R, Tavecchio F, Temnikov P, Terauchi K, Terzić T, Teshima M, Tosti L, Truzzi S, Tutone A, Ubach S, van Scherpenberg J, Vazquez Acosta M, Ventura S, Verguilov V, Viale I, Vigorito CF, Vitale V, Vovk I, Walter R, Will M, Wunderlich C, Yamamoto T, Zarić D, Hiroshima N, and Kohri K

Abstract

Linelike features in TeV γ rays constitute a "smoking gun" for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite γ-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic telescope system reaching γ-ray energies up to 100 TeV. We improved the sensitivity to spectral lines at high energies using large-zenith-angle observations and a novel background modeling method within a maximum-likelihood analysis in the energy domain. No linelike spectral feature is found in our analysis. Therefore, we constrain the cross section for dark matter annihilation into two photons to ⟨σv⟩≲5×10^{-28}  cm^{3} s^{-1} at 1 TeV and ⟨σv⟩≲1×10^{-25}  cm^{3} s^{-1} at 100 TeV, achieving the best limits to date for a dark matter mass above 20 TeV and a cuspy dark matter profile at the Galactic Center. Finally, we use the derived limits for both cuspy and cored dark matter profiles to constrain supersymmetric wino models.

Published
2023
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9. Polarized blazar X-rays imply particle acceleration in shocks.

Author

Liodakis I, Marscher AP, Agudo I, Berdyugin AV, Bernardos MI, Bonnoli G, Borman GA, Casadio C, Casanova VC, Cavazzuti E, Rodriguez Cavero N, Di Gesu L, Di Lalla N, Donnarumma I, Ehlert SR, Errando M, Escudero J, Garcı A-Comas M, Agı S-González B, Husillos C, Jormanainen J, Jorstad SG, Kagitani M, Kopatskaya EN, Kravtsov V, Krawczynski H, Lindfors E, Larionova EG, Madejski GM, Marin F, Marchini A, Marshall HL, Morozova DA, Massaro F, Masiero JR, Mawet D, Middei R, Millar-Blanchaer MA, Myserlis I, Negro M, Nilsson K, O'Dell SL, Omodei N, Pacciani L, Paggi A, Panopoulou GV, Peirson AL, Perri M, Petrucci PO, Poutanen J, Puccetti S, Romani RW, Sakanoi T, Savchenko SS, Sota A, Tavecchio F, Tinyanont S, Vasilyev AA, Weaver ZR, Zhovtan AV, Antonelli LA, Bachetti M, Baldini L, Baumgartner WH, Bellazzini R, Bianchi S, Bongiorno SD, Bonino R, Brez A, Bucciantini N, Capitanio F, Castellano S, Ciprini S, Costa E, De Rosa A, Del Monte E, Di Marco A, Doroshenko V, Dovčiak M, Enoto T, Evangelista Y, Fabiani S, Ferrazzoli R, Garcia JA, Gunji S, Hayashida K, Heyl J, Iwakiri W, Karas V, Kitaguchi T, Kolodziejczak JJ, La Monaca F, Latronico L, Maldera S, Manfreda A, Marinucci A, Matt G, Mitsuishi I, Mizuno T, Muleri F, Ng SC, Oppedisano C, Papitto A, Pavlov GG, Pesce-Rollins M, Pilia M, Possenti A, Ramsey BD, Rankin J, Ratheesh A, Sgró C, Slane P, Soffitta P, Spandre G, Tamagawa T, Taverna R, Tawara Y, Tennant AF, Thomas NE, Tombesi F, Trois A, Tsygankov S, Turolla R, Vink J, Weisskopf MC, Wu K, Xie F, and Zane S

Abstract

Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to around 1 TeV. Although the jets are known to be ultimately powered by a supermassive black hole, how the particles are accelerated to such high energies has been an unanswered question. The process must be related to the magnetic field, which can be probed by observations of the polarization of light from the jets. Measurements of the radio to optical polarization-the only range available until now-probe extended regions of the jet containing particles that left the acceleration site days to years earlier 1-3 , and hence do not directly explore the acceleration mechanism, as could X-ray measurements. Here we report the detection of X-ray polarization from the blazar Markarian 501 (Mrk 501). We measure an X-ray linear polarization degree Π X of around 10%, which is a factor of around 2 higher than the value at optical wavelengths, with a polarization angle parallel to the radio jet. This points to a shock front as the source of particle acceleration and also implies that the plasma becomes increasingly turbulent with distance from the shock., (© 2022. The Author(s).)

Published
2022
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