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arXiv 2023年

作者： Abe, H. Abe, S. Acciari, V.A. Agudo, I. Aniello, T. Ansoldi, S. Antonelli, L.A. Arbet Engels, A. Arcaro, C. Artero, M. Asano, K. Baack, D. Babić, A. Baquero, A. Barres de Almeida, U. Batković, I. Baxter, J. Becerra González, J. Bernardini, E. Bernete, J. Berti, A. Besenrieder, J. Bigongiari, C. Biland, A. Blanch, O. Bonnoli, G. Bošnjak, Ž. Burelli, I. Busetto, G. Campoy-Ordaz, A. Carosi, A. Carosi, R. Carretero-Castrillo, M. Castro-Tirado, A.J. Chai, Y. Cifuentes, A. Cikota, S. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D’Amico, G. D’Ammando, F. 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. Dominis Prester, D. Dorner, D. Doro, M. Elsaesser, D. Emery, G. Escudero, J. Fariña, L. Fattorini, A. Foffano, L. Font, L. Fukami, S. Fukazawa, Y. García López, R.J. Gasparyan, S. Gaug, M. Giesbrecht Paiva, J.G. Giglietto, N. Giordano, F. Gliwny, P. Grau, R. Green, J.G. Hadasch, D. Hahn, A. Heckmann, L. Herrera, J. Hrupec, D. Hütten, M. Imazawa, R. Inada, T. Iotov, R. Ishio, K. Jiménez Martínez, I. Jormanainen, J. Kerszberg, D. Kluge, G.W. Kobayashi, Y. Kouch, P.M. Kubo, H. Kushida, J. Láinez Lezáun, M. Lamastra, A. Leone, F. Lindfors, E. Linhoff, L. Lombardi, S. Longo, F. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. Machado de Oliveira Fraga, B. Majumdar, P. Makariev, M. Maneva, G. Mang, N. Manganaro, M. Mariotti, M. Martínez, M. Martínez-Chicharro, M. Mas-Aguilar, A. Mazin, D. Menchiari, S. Mender, S. Miceli, D. Miener, T. Miranda, J.M. Mirzoyan, R. Molero González, M. Molina, E. Mondal, H.A. Moralejo, A. Morcuende, D. Nakamori, T. Nanci, C. Neustroev, V. Nigro, C. Nikolić, L. Nishijima, K. Njoh Ekoume, T. Noda, K. Nozaki, S. Ohtani, Y. Okumura, A. Otero-Santos, J. Paiano, S. Palatiello, M. Paneque, D. Paoletti, R. Paredes, J.M. Pavlović, D. Persic, M. Pihet, M. Pirola, G. Podobnik, F. Prada Moroni, P.G. The University of Tokyo Chiba Kashiwa277-8582 Japan Instituto de Astrofísica de Canarias Dpto. de Astrofísica Universidad de La Laguna Tenerife La LagunaE-38200 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik MünchenD-80805 Germany Università di Padova INFN PadovaI-35131 Italy The Barcelona InsINAF - Istituto di Radioastronomia Via Gobetti 101 BolognaI-40129 Italy Bellaterra BarcelonaE-08193 Spain Technische Universität Dortmund DortmundD-44221 Germany Zagreb10000 Croatia IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain Rio de Janeiro22290-180 Brazil Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain ETH Zürich ZürichCH-8093 Switzerland Departament de Física CERES-IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Università di Pisa INFN Pisa PisaI-56126 Italy Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Department for Physics and Technology University of Bergen Norway INFN MAGIC Group: INFN Sezione di Catania Dipartimento di Fisica e Astronomia University of Catania CataniaI-95123 Italy INFN MAGIC Group: INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy INFN MAGIC Group: INFN Sezione di Bari Dipartimento Interateneo di Fisica Università e del Politecnico di Bari BariI-70125 Italy Croatian MAGIC Group University of Rijeka Faculty of Physics Rijeka51000 Croatia University of Geneva Chemin d’Ecogia 16 VersoixCH-1290 Switzerland Japanese MAGIC Group: Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan Armenian MAGIC Group: ICRANet-Armenia Yerevan0019 Armenia University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Pola

Aims. The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron spectral energy distribution (SED) peak energy νsynch,p above 1 keV). While those extreme states were so far observed only during high flux levels, additional multi-year observing campaigns are required to achieve a coherent picture. Here, we report the longest investigation of the source from radio to very high energy (VHE) performed so far, focusing on a systematic characterisation of the intermittent extreme states. Methods. We organised a monitoring campaign covering a 3-year period from 2019 to 2021. More than ten instruments participated in the observations in order to cover the emission from radio to VHE. In particular, sensitive X-ray measurements by XMM-Newton, NuSTAR, and AstroSat took place simultaneously with multi-hour MAGIC observations, providing an unprecedented constraint of the two SED components for this blazar. Results. While our results confirm that 1ES 2344+514 typically exhibits νsynch,p > 1 keV during elevated flux periods, we also find periods where the extreme state coincides with low flux activity. A strong spectral variability thus happens in the quiescent state, and is likely caused by an increase of the electron acceleration efficiency without a change in the electron injection luminosity. On the other hand, we also report a strong X-ray flare (among the brightest for 1ES 2344+514) without a significant shift of νsynch,p. During this particular flare, the X-ray spectrum is among the softest of the campaign. It unveils complexity in the spectral evolution, where the common "harder-when-brighter" trend observed in BL Lacs is violated. By combining Swift-XRT and Swift-UVOT measurements during a low and hard X-ray state, we find an excess of the UV flux with respect to an extrapolation of the X-ray spectrum to lower energies. This "UV excess" implies that at least two regions contribute significantly to the infrared/optical/ultraviolet/

关键词： Galaxies

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The polarized image of a synchrotron emitting ring of gas orbiting a Black Hole

arXiv

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arXiv 2021年

作者： Narayan, Ramesh Palumbo, Daniel C.M. Johnson, Michael D. Gelles, Zachary Himwich, Elizabeth Chang, Dominic O. Ricarte, Angelo Dexter, Jason Gammie, Charles F. Chael, Andrew A. Akiyama, Kazunori Alberdi, Antxon Alef, Walter Algaba, Juan Carlos Anantua, Richard Asada, Keiichi Azulay, Rebecca Baczko, Anne-Kathrin Ball, David Baloković, Mislav Barrett, John Benson, Bradford A. Bintley, Dan Blackburn, Lindy Blundell, Raymond Boland, Wilfred Bouman, Katherine L. Bower, Geoffrey C. Boyce, Hope Bremer, Michael Brinkerink, Christiaan D. Brissenden, Roger Britzen, Silke Broderick, Avery E. Broguiere, Dominique Bronzwaer, Thomas Byun, Do-Young Carlstrom, John E. Chan, Chi-Kwan Chatterjee, Shami Chatterjee, Koushik Chen, Ming-Tang Chen, Yongjun Chesler, Paul M. Cho, Ilje Christian, Pierre Conway, John E. Cordes, James M. Crawford, Thomas M. Crew, Geoffrey B. Cruz-Osorio, Alejandro Cui, Yuzhu Davelaar, Jordy de Laurentis, Mariafelicia Deane, Roger Dempsey, Jessica Desvignes, Gregory Doeleman, Sheperd S. Eatough, Ralph P. Falcke, Heino Farah, Joseph Fish, Vincent L. Fomalont, Ed Alyson Ford, H. Fraga-Encinas, Raquel Friberg, Per Fromm, Christian M. Fuentes, Antonio Galison, Peter García, Roberto Gentaz, Olivier Georgiev, Boris Goddi, Ciriaco Gold, Roman Gómez, José L. Gómez-Ruiz, Arturo I. Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Haggard, Daryl Hecht, Michael H. Hesper, Ronald Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, David H. Ikeda, Shiro Inoue, Makoto Issaoun, Sara James, David J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Jimenez-Rosales, Alejandra Jorstad, Svetlana Jung, Taehyun Karami, Mansour Karuppusamy, Ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kino, Motoki Koay, Jun Yi Kofuji, Yutaro Koch, Patrick M. Koyama, Shoko Kramer, Michael Kramer, Carsten Krichbaum, Thomas P. Kuo, Cheng-Yu Lauer, Tod R. Lee, Sang-Sung Levis, Aviad Li, Yan-Rong Li, Zhiyuan Lindqvist, Michael Lico, Rocco Lindahl, Greg Liu, Jun Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Black Hole Initiative at Harvard University 20 Garden Street CambridgeMA02138 United States Center for the Fundamental Laws of Nature Harvard University CambridgeMA02138 United States JILA Department of Astrophysical and Planetary Sciences University of Colorado BoulderCO80309 United States Department of Physics University of Illinois at Urbana-Champaign 1110 West Green Street UrbanaIL61801 United States Department of Astronomy University of Illinois at Urbana-Champaign 1002 West Green Street UrbanaIL61801 United States Princeton Center for Theoretical Science Jadwin Hall Princeton University PrincetonNJ08544 United States NASA Hubble Fellowship Program Einstein United States Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road WestfordMA01886 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n GranadaE-18008 Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Department of Physics Faculty of Science University of Malaya Kuala Lumpur50603 Malaysia Center for Astrophysics - Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Center for Computational Astrophysics Flatiron Institute 162 Fifth Avenue New YorkNY10010 United States Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Departament d'Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 Burjassot ValènciaE-46100 Spain Observatori Astronòmic Universitat de València C. Catedrático José Beltrán 2 Paterna ValènciaE-46980 Spain Steward Observatory Department of Astronomy University of Arizona 933 N. Cherry Ave. TucsonAZ85721 United States Fermi National Accelerator Laboratory

Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field in the emitting region, relativistic motion of the gas, strong gravitational lensing by the black hole, and parallel transport in the curved spacetime. We explore these effects using a simple model of an axisymmetric, equatorial accretion disk around a Schwarzschild black hole. By using an approximate expression for the null geodesics derived by Beloborodov (2002) and conservation of the Walker-Penrose constant, we provide analytic estimates for the image polarization. We test this model using currently favored general relativistic magnetohydrodynamic simulations of M87*, using ring parameters given by the simulations. For a subset of these with modest Faraday effects, we show that the ring model broadly reproduces the polarimetric image morphology. Our model also predicts the polarization evolution for compact flaring regions, such as those observed from Sgr A* with GRAVITY. With suitably chosen parameters, our simple model can reproduce the EVPA pattern and relative polarized intensity in Event Horizon Telescope images of M87*. Under the physically motivated assumption that the magnetic field trails the fluid velocity, this comparison is consistent with the clockwise rotation inferred from total intensity images. Copyright © 2021, The Authors. All rights reserved.

关键词： Black holes

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A Demonstration of extremely low latency γ-ray, X-ray & UV follow-up of a millisecond radio transient

arXiv

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arXiv 2020年

作者： Tohuvavohu, Aaron Law, Casey J. Kennea, Jamie A. Adams, Elizabeth A.K. Aggarwal, Kshitij Bower, Geoffrey Burke-Spolaor, Sarah Butler, Bryan J. Cannon, John M. Cenko, S. Bradley DeLaunay, James Demorest, Paul Drout, Maria R. Evans, Philip A. Hirschauer, Alec S. Lazio, T.J.W. Linford, Justin Marshall, Francis E. McQuinn, Kristen B.W. Petroff, Emily Skillman, Evan D. Department of Astronomy & Astrophysics University of Toronto 50 St. George Street TorontoONM5S 3H4 Canada Cahill Center for Astronomy and Astrophysics MC 249-17 California Institute of Technology PasadenaCA91125 United States Department of Astronomy & Astrophysics Penn State University PA United States ASTRON Netherlands Institute for Radio Astronomy Oude Hoogeveensedijk 4 Dwingeloo7991 PD Netherlands Kapteyn Astronomical Institute University of Groningen Postbus 800 Groningen9700 AV Netherlands Center for Gravitational Waves and Cosmology West Virginia University Chestnut Ridge Research Building MorgantownWV26505 Department of Physics and Astronomy West Virginia University MorgantownWV26506 ASIAA 645 N. A’ohoku Pl HiloHI96720 Affiliate Graduate Faculty UH Manoa Physics and Astronomy CIFAR Azrieli Global Scholars program CIFAR Toronto Canada National Radio Astronomy Observatory SocorroNM87801 United States Department of Physics & Astronomy Macalester College 1600 Grand Avenue Saint PaulMN55105 NASA Goddard Space Flight Center GreenbeltMD United States University of Leicester X-ray and Observational Astronomy Group School of Physics and Astronomy University Road LeicesterLE1 7RH United Kingdom Space Telescope Science Institute Jet Propulsion Laboratory California Institute of Technology M/S 67-201 4800 Oak Grove Dr. PasadenaCA91109 Rutgers University Department of Physics and Astronomy 136 Frelinghuysen Road PiscatawayNJ08854 United States Anton Pannekoek Institute University of Amsterdam Postbus 94249 Amsterdam1090 GE Netherlands Minnesota Institute for Astrophysics University of Minnesota 116 Church St. SE MinneapolisMN55455

We report results of a novel high-energy follow-up observation of a potential Fast Radio Burst. The radio burst was detected by VLA/realfast and followed-up by the Neil Gehrels Swift Observatory in very low latency utilizing new operational capabilities of Swift (Tohuvavohu et al. 2020), with pointed soft X-ray and UV observations beginning at T0+32 minutes, and hard X-ray/gamma-ray event data saved around T0. These observations are > 10x faster than previous X-ray/UV follow-up of any radio transient to date. No emission is seen coincident with the FRB candidate at T0, with a 0.2s fluence 5σ upper limit of 1.35 × 10−8 erg cm−2 (14-195 keV) for a SGR 1935+2154-like flare, nor at T0+32 minutes down to 3σ upper limits of 22.18 AB mag in UVOT u band, and 3.33 × 10−13 erg cm−2 s−1 from 0.3-10 keV for the 2 ks observation. The candidate FRB alone is not significant enough to be considered astrophysical, so this note serves as a technical demonstration. These new Swift operational capabilities will allow future FRB detections to be followed up with XRT/UVOT at even lower latencies than demonstrated here: 15-20 minutes should be regularly achievable, and 5-10 minutes occasionally achievable. We encourage FRB detecting facilities to release alerts in low latency to enable this science. Copyright © 2020, The Authors. All rights reserved.

关键词： Gamma rays

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Constraints on axion-like particles with the Perseus Galaxy Cluster with MAGIC

arXiv

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arXiv 2024年

作者： Abe, H. Abe, S. Abhir, J. Acciari, V.A. Agudo, I. Aniello, T. Ansoldi, S. Antonelli, L.A. Engels, A. Arbet Arcaro, C. Artero, M. Asano, K. Baack, D. Babić, A. Baquero, A. de Almeida, U. Barres Barrio, J.A. Batković, I. Baxter, J. González, J. Becerra Bednarek, W. Bernardini, E. Bernete, J. Berti, A. Besenrieder, J. Bigongiari, C. Biland, A. Blanch, O. Bonnoli, G. Bošnjak, Ž. Burelli, I. Busetto, G. Campoy-Ordaz, A. Carosi, A. Carosi, R. Carretero-Castrillo, M. Castro-Tirado, A.J. Ceribella, G. Chai, Y. Cifuentes, A. Cikota, S. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D’Amico, G. D’Elia, V. Da Vela, P. Dazzi, F. De Angelis, A. De Lotto, B. Del Popolo, A. Delgado, J. Mendez, C. Delgado Depaoli, D. Di Pierro, F. Di Venere, L. Prester, D. Dominis Donini, A. Dorner, D. Doro, M. Elsaesser, D. Emery, G. Escudero, J. Fariña, L. Fattorini, A. Foffano, L. Font, L. Fukami, S. Fukazawa, Y. López, R.J. García Garczarczyk, M. Gasparyan, S. Gaug, M. Paiva, J.G. Giesbrecht Giglietto, N. Giordano, F. Gliwny, P. Godinović, N. Grau, R. Green, D. Green, J.G. Hadasch, D. Hahn, A. Hassan, T. Heckmann, L. Herrera, J. Hrupec, D. Hütten, M. Imazawa, R. Inada, T. Iotov, R. Ishio, K. Martínez, I. Jiménez Jormanainen, J. Kerszberg, D. Kluge, G.W. Kobayashi, Y. Kouch, P.M. Kubo, H. Kushida, J. Lezáun, M. Láinez Lamastra, A. Leone, F. Lindfors, E. Linhoff, L. Lombardi, S. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. de Oliveira Fraga, B. Machado Majumdar, P. Makariev, M. Maneva, G. Mang, N. Manganaro, M. Mangano, S. Mannheim, K. Mariotti, M. Martínez, M. Martínez-Chicharro, M. Mas-Aguilar, A. Mazin, D. Menchiari, S. Mender, S. Miceli, D. Miener, T. Miranda, J.M. Mirzoyan, R. González, M. Molero Molina, E. Mondal, H.A. Moralejo, A. Morcuende, D. Nakamori, T. Nanci, C. Nava, L. Neustroev, V. Nickel, L. Rosillo, M. Nievas Nigro, C. Nikolić, L. Nilsson, K. Nishijima, K. Ekoume, T. Njoh Noda, K. Nozaki, S. Ohtani, Y. Okumura, A. The University of Tokyo Chiba Kashiwa277-8582 Japan ETH Zürich ZürichCH-8093 Switzerland Instituto de Astrofísica de Canarias Dpto. de Astrofísica Universidad de La Laguna Tenerife La LagunaE-38200 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik MünchenD-80805 Germany Università di Padova INFN PadovaI-35131 Italy Bellaterra BarcelonaE-08193 Spain Technische Universität Dortmund DortmundD-44221 Germany Zagreb10000 Croatia IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain URCA RJ Rio de Janeiro22290-180 Brazil University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain Departament de Física CERES-IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Università di Pisa INFN Pisa PisaI-56126 Italy Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Department for Physics and Technology University of Bergen Norway INFN MAGIC Group INFN Sezione di Catania Dipartimento di Fisica e Astronomia University of Catania CataniaI-95123 Italy INFN MAGIC Group INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy INFN MAGIC Group INFN Sezione di Bari Dipartimento Interateneo di Fisica Università e del Politecnico di Bari BariI-70125 Italy Croatian MAGIC Group University of Rijeka Faculty of Physics Rijeka51000 Croatia University of Geneva Chemin d’Ecogia 16 VersoixCH-1290 Switzerland Japanese MAGIC Group Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan ZeuthenD-15738 Germany Armenian MAGIC Group ICRANet-Armenia Yerevan0019 Armenia Split21000 Croatia Croatian MAGIC Group Josip Jura

Axion-like particles (ALPs) are pseudo-Nambu-Goldstone bosons that emerge in various theories beyond the standard model. These particles can interact with high-energy photons in external magnetic fields, influencing the observed gamma-ray spectrum. This study analyzes 41.3 hrs of observational data from the Perseus Galaxy Cluster collected with the MAGIC telescopes. We focused on the spectra the radio galaxy in the center of the cluster: NGC 1275. By modeling the magnetic field surrounding this target, we searched for spectral indications of ALP presence. Despite finding no statistical evidence of ALP signatures, we were able to exclude ALP models in the sub-micro electronvolt range. Our analysis improved upon previous work by calculating the full likelihood and statistical coverage for all considered models across the parameter space. Consequently, we achieved the most stringent limits to date for ALP masses around 50 neV, with cross sections down to gaγ = 3 × 10−12 GeV−1 Copyright © 2024, The Authors. All rights reserved.

关键词： Gamma rays

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Combined search in dwarf spheroidal galaxies for branon dark matter annihilation signatures with the MAGIC telescopes

arXiv

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arXiv 2024年

作者： Abe, S. Abhir, J. Abhishek, A. Acciari, V.A. Aguasca-Cabot, A. Agudo, I. Aniello, T. Ansoldi, S. Engels, A. Arbet Arcaro, C. Asano, K. Baack, D. Babić, A. de Almeida, U. Barres Barrio, J.A. Batković, I. Bautista, A. Baxter, J. González, J. Becerra Bednarek, W. Bernardini, E. Bernete, J. Berti, A. Besenrieder, J. Bigongiari, C. Biland, A. Blanch, O. Bonnoli, G. Bošnjak, Ž. Bronzini, E. Burelli, I. Campoy-Ordaz, A. Carosi, R. Carretero-Castrillo, M. Castro-Tirado, A.J. Cerasole, D. Ceribella, G. Chai, Y. Cifuentes, A. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D’Amico, G. D’Elia, V. Da Vela, P. Dazzi, F. De Angelis, A. De Lotto, B. de Menezes, R. Delgado, J. Mendez, C. Delgado Di Pierro, F. Di Tria, R. Di Venere, L. Prester, D. Dominis Donini, A. Dorner, D. Doro, M. Elsaesser, D. Escudero, J. Fariña, L. Fattorini, A. Foffano, L. Font, L. Fröse, S. Fukami, S. Fukazawa, Y. López, R.J. García Garczarczyk, M. Gasparyan, S. Gaug, M. Paiva, J.G. Giesbrecht Giglietto, N. Giordano, F. Gliwny, P. Gradetzke, T. Grau, R. Green, D. Green, J.G. Günther, P. Hadasch, D. Hahn, A. Hassan, T. Heckmann, L. Llorente, J. Herrera Hrupec, D. Imazawa, R. Ishio, K. Martínez, I. Jiménez Jormanainen, J. Kankkunen, S. Kayanoki, T. Kerszberg, D. Kluge, G.W. Kobayashi, Y. Kouch, P.M. Kubo, H. Kushida, J. Láinez, M. Lamastra, A. Leone, F. Lindfors, E. Lombardi, S. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. Lyard, E. Majumdar, P. Makariev, M. Maneva, G. Manganaro, M. Mangano, S. Mannheim, K. Mariotti, M. Martínez, M. Martínez-Chicharro, M. Mas-Aguilar, A. Mazin, D. Menchiari, S. Mender, S. Miceli, D. Miener, T. Miranda, J.M. Mirzoyan, R. González, M. Molero Molina, E. Mondal, H.A. Moralejo, A. Morcuende, D. Nakamori, T. Nanci, C. Neustroev, V. Rosillo, M. Nievas Nigro, C. Nikolić, L. Nishijima, K. Ekoume, T. Njoh Nozaki, S. Okumura, A. Otero-Santos, J. Paiano, S. Paneque, D. Paoletti, R. Paredes, J.M. Peresano, M. Persic, M. Pihet, M. The University of Tokyo Chiba Kashiwa277-8582 Japan ETH Zürich ZürichCH-8093 Switzerland Università di Siena INFN Pisa SienaI-53100 Italy Bellaterra BarcelonaE-08193 Spain Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik GarchingD-85748 Germany Università di Padova INFN PadovaI-35131 Italy Technische Universität Dortmund DortmundD-44221 Germany Zagreb10000 Croatia URCA RJ Rio de Janeiro22290-180 Brazil IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain Instituto de Astrofísica de Canarias and Dpto. de Astrofísica Universidad de La Laguna Tenerife La LagunaE-38200 Spain University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain Departament de Física CERES-IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Università di Pisa INFN Pisa PisaI-56126 Italy INFN MAGIC Group INFN Sezione di Bari Dipartimento Interateneo di Fisica dell’Università e del Politecnico di Bari BariI-70125 Italy Department for Physics and Technology University of Bergen Norway INFN MAGIC Group INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy Croatian MAGIC Group University of Rijeka Faculty of Physics Rijeka51000 Croatia Universität Würzburg WürzburgD-97074 Germany Japanese MAGIC Group: Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan ZeuthenD-15738 Germany Armenian MAGIC Group: ICRANet-Armenia Yerevan0019 Armenia Croatian MAGIC Group Josip Juraj Strossmayer University of Osijek Department of Physics Osijek31000 Croatia Finnish MAGIC Group Finnish C

Massive brane fluctuations, called branons, behave as weakly interacting massive particles, which is one of the most favored class of candidates to fulfill the role of the dark matter (DM), an elusive kind of matter beyond the Standard Model. We present a multi-target search in dwarf spheroidal galaxies for branon DM annihilation signatures with a total exposure of 354 hours with the ground-based gamma-ray telescope system MAGIC. This search led to the most constraining limits on branon DM in the sub-TeV and multi-TeV DM mass range. Our most stringent limit on the thermally-averaged annihilation cross-section (at 95% confidence level) corresponds to 〈σv〉 1.9 × 10−24 cm3s−1 at a branon mass of ∼ 1.5 TeV. © 2024, CC BY-SA.

关键词： Dark Matter

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First characterization of the emission behavior of Mrk421 from radio to VHE gamma rays with simultaneous X-ray polarization measurements

arXiv

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arXiv 2023年

作者： Abe, S. Abhir, J. Acciari, V.A. Agudo, I. Aniello, T. Ansoldi, S. Antonelli, L.A. Arbet Engels, A. Arcaro, C. Artero, M. Asano, K. Babić, A. Baquero, A. Barres de Almeida, U. Barrio, J.A. Batković, I. Baxter, J. Becerra González, J. Bednarek, W. Bernardini, E. Bernete, J. Berti, A. Besenrieder, J. Bigongiari, C. Biland, A. Blanch, O. Bonnoli, G. Bošnjak, Ž. Burelli, I. Busetto, G. Campoy-Ordaz, A. Carosi, A. Carosi, R. Carretero-Castrillo, M. Castro-Tirado, A.J. Ceribella, G. Chai, Y. Cifuentes, A. Cikota, S. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D'Ammando, F. D'Amico, G. D'Elia, V. Da Vela, P. Dazzi, F. De Angelis, A. De Lotto, B. de Menezes, R. Del Popolo, A. Delgado, J. Delgado Mendez, C. Di Pierro, F. Di Venere, L. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Elsaesser, D. Emery, G. Escudero, J. Fariña, L. Fattorini, A. Foffano, L. Font, L. Fröse, S. Fukami, S. Fukazawa, Y. García López, R.J. Garczarczyk, M. Gasparyan, S. Gaug, M. Giesbrecht Paiva, J.G. Giglietto, N. Giordano, F. Gliwny, P. Godinović, N. Gradetzke, T. Grau, R. Green, D. Green, J.G. Günther, P. Hadasch, D. Hahn, A. Hassan, T. Heckmann, L. Herrera, J. Hrupec, D. Hütten, M. Imazawa, R. Inada, T. Ishio, K. Jiménez Martínez, I. Jormanainen, J. Kerszberg, D. Kluge, G.W. Kobayashi, Y. Kouch, P.M. Kubo, H. Kushida, J. Láinez Lezáun, M. Lamastra, A. Leone, F. Lindfors, E. Linhoff, L. Lombardi, S. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. Machado de Oliveira Fraga, B. Majumdar, P. Makariev, M. Maneva, G. Mang, N. Manganaro, M. Mangano, S. Mannheim, K. Mariotti, M. Martínez, M. Martínez-Chicharro, M. Mas-Aguilar, A. Mazin, D. Menchiari, S. Mender, S. Miceli, D. Miener, T. Miranda, J.M. Mirzoyan, R. Molero González, M. Molina, E. Mondal, H.A. Moralejo, A. Morcuende, D. Nakamori, T. Nanci, C. Nava, L. Neustroev, V. Nickel, L. Nievas Rosillo, M. Nigro, C. Nikolić, L. Nilsson, K. Nishijima, K. Njoh Ekoume, T. Noda, K. Nozaki, S. The University of Tokyo Chiba Kashiwa277-8582 Japan ETH Zürich ZürichCH-8093 Switzerland Instituto de Astrofísica de Canarias Dpto. de Astrofísica Universidad de La Laguna Tenerife La LagunaE-38200 Spain Instituto de Astrofísica de Andalucía CSIC Glorieta de la As-tronomía s/n Granada18008 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik MünchenD-80805 Germany Università di Padova INFN PadovaI-35131 Italy Bellaterra BarcelonaE-08193 Spain Zagreb10000 Croatia IPARCOS Institute EMFTEL Department Universidad Com-plutense de Madrid MadridE-28040 Spain URCA RJ Rio de Janeiro22290-180 Brazil University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain Departament de Física CERES IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Università di Pisa INFN Pisa PisaI-56126 Italy Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Department for Physics and Technology University of Bergen Norway INFN MAGIC Group INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy INFN MAGIC Group INFN Sezione di Catania Dipartimento di Fisica e Astronomia University of Catania CataniaI-95123 Italy INFN MAGIC Group INFN Sezione di Bari Dipartimento In-terateneo di Fisica Università e del Politecnico di Bari BariI-70125 Italy Croatian MAGIC Group University of Rijeka Faculty of Physics Rijeka51000 Croatia Technische Universität Dortmund DortmundD-44221 Germany University of Geneva Chemin d'Ecogia 16 VersoixCH-1290 Switzerland Japanese MAGIC Group: Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan ZeuthenD-15738 Germany Armenian MAGIC Group: ICRANet-Armenia Yerevan0019 Armenia Split21000 Croatia Universität Würzburg Würzb

Aims. We perform the first broadband study of Mrk 421 from radio to TeV gamma rays with simultaneous measurements of the X-ray polarization from IXPE. Methods. The data were collected within an extensive multiwavelength campaign organized between May and June 2022 using MAGIC, FermiLAT, NuSTAR, XMM-Newton, Swift, and several optical and radio telescopes to complement IXPE. Results. During the IXPE exposures, the measured 0.2-1 TeV flux is close to the quiescent state and ranges from 25% to 50% of the Crab Nebula without intra-night variability. Throughout the campaign, the VHE and X-ray emission are positively correlated at a 4σ significance level. The IXPE measurements unveil a X-ray polarization degree that is a factor of 2-5 higher than in the optical/radio bands;that implies an energy-stratified jet in which the VHE photons are emitted co-spatially with the X-rays, in the vicinity of a shock front. The June 2022 observations exhibit a rotation of the X-ray polarization angle. Despite no simultaneous VHE coverage being available during a large fraction of the swing, the Swift-XRT monitoring unveils an X-ray flux increase with a clear spectral hardening. It suggests that flares in high synchrotron peaked blazars can be accompanied by a polarization angle rotation, as observed in some flat spectrum radio quasars. Finally, during the polarization angle rotation, NuSTAR data reveal two contiguous spectral hysteresis loops in opposite directions (clockwise and counter-clockwise), implying important changes in the particle acceleration efficiency on ∼hour timescales. Copyright © 2023, The Authors. All rights reserved.

关键词： Gamma rays

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Publisher Correction: Firn on ice sheets

引用

Nature Reviews Earth & Environment 2024年 330页

作者： Charles Amory Christo Buizert Sammie Buzzard Elizabeth Case Nicole Clerx Riley Culberg Rajashree Tri Datta Devon Dunmire Jan T. M. Lenaerts Megan Thompson-Munson Nander Wever Rahul Dey Reinhard Drews Falk M. Oraschewski Clare Eayrs Nicolaj Hansen Sebastian B. Simonsen Angelika Humbert Athul Kaitheri Kaitlin Keegan Ian McDowell Peter Kuipers Munneke Stef Lhermitte Sophie de Roda Husman Bert Wouters Doug Mair Jessica Mejia Colin R. Meyer Elizabeth Morris Dorothea Moser Elizabeth R. Thomas Emma Pearce Nicole-Jeanne Schlegel Timm Schultz C. Max Stevens Institut des Géosciences de l’Environnement University Grenoble Alpes CNRS Grenoble France College of Earth Ocean and Atmospheric Sciences Oregon State University Corvallis OR USA School of Earth and Environmental Sciences Cardiff University Cardiff UK Department of Geography and Environmental Sciences Northumbria University Newcastle upon Tyne UK Department of Earth and Environmental Sciences Columbia University NY USA Department of Geosciences Université de Fribourg Fribourg Switzerland Department of Earth and Atmospheric Sciences Cornell University Ithaca NY USA Department of Atmospheric and Oceanic Sciences University of Colorado Boulder Boulder CO USA Cooperative Institute for Research in Environmental Sciences (CIRES) University of Colorado Boulder Boulder CO USA WSL Institute for Snow and Avalanche Research SLF Davos Switzerland National Centre for Polar and Ocean Research (NCPOR) Ministry of Earth Sciences Vasco da Gama Goa India Department of Geosciences University of Tübingen Tübingen Germany Center for Global Sea Level Change New York University Abu Dhabi Abu Dhabi UAE Department of Glacial Environment Research Korea Polar Research Institute Incheon Republic of Korea Geodesy and Earth Observation DTU Space Technical University of Denmark Kongens Lyngby Denmark Danish Meteorological Institute Copenhagen Denmark Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research Bremerhaven Germany Faculty of Geosciences University of Bremen Bremen Germany Observatoire de la Côte d’Azur Université Côte d’Azur CNRS Valbonne France Department of Geological Sciences and Engineering University of Nevada Reno USA Graduate Program of Hydrologic Sciences University of Nevada Reno NV USA Institute for Marine and Atmospheric Research (IMAU) Utrecht University Utrecht The Netherlands Department of Earth and Environmental Sciences KU Leuven Leuven Belgium Department of Geoscience and Remote Sensing Delft University of Technology (TUDel

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The variability of the black-hole image in M87 at the dynamical time scale

arXiv

引用

arXiv 2021年

作者： Satapathy, Kaushik Psaltis, Dimitrios Özel, Feryal Medeiros, Lia Dougall, Sean T. Chan, Chi-Kwan Wielgus, Maciek Prather, Ben S. Wong, George N. Gammie, Charles F. Akiyama, Kazunori Alberdi, Antxon Alef, Walter Algaba, Juan Carlos Anantua, Richard Asada, Keiichi Azulay, Rebecca Baczko, Anne-Kathrin Ball, David Baloković, Mislav Barrett, John Benson, Bradford A. Bintley, Dan Blackburn, Lindy Blundell, Raymond Boland, Wilfred Bouman, Katherine L. Bower, Geoffrey C. Boyce, Hope Bremer, Michael Brinkerink, Christiaan D. Brissenden, Roger Britzen, Silke Broderick, Avery E. Broguiere, Dominique Bronzwaer, Thomas Bustamente, Sandra Byun, Do-Young Carlstrom, John E. Chael, Andrew Chatterjee, Koushik Chatterjee, Shami Chen, Ming-Tang Chen, Yongjun Cho, Ilje Christian, Pierre Conway, John E. Cordes, James M. Crawford, Thomas M. Crew, Geoffrey B. Cruz-Osorio, Alejandro Cui, Yuzhu Davelaar, Jordy de Laurentis, Mariafelicia Deane, Roger Dempsey, Jessica Desvignes, Gregory Dexter, Jason Doeleman, Sheperd S. Eatough, Ralph P. Falcke, Heino Farah, Joseph Fish, Vincent L. Fomalont, Ed Alyson Ford, H. Fraga-Encinas, Raquel Friberg, Per Fromm, Christian M. Fuentes, Antonio Galison, Peter García, Roberto Gentaz, Olivier Georgiev, Boris Goddi, Ciriaco Gold, Roman Gómez-Ruiz, Arturo I. Gómez, José L. Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Haggard, Daryl Hecht, Michael H. Hesper, Ronald Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, David H. Ikeda, Shiro Inoue, Makoto Issaoun, Sara James, David J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Jimenez-Rosales, Alejandra Johnson, Michael D. Jorstad, Svetlana Jung, Taehyun Karami, Mansour Karuppusamy, Ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kino, Motoki Koay, Jun Yi Kofuji, Yutaro Koch, Patrick M. Koyama, Shoko Kramer, Carsten Kramer, Michael Krichbaum, Thomas P. Kuo, Cheng-Yu Lauer, Tod R. Lee, Sang-Sung Levis, Aviad Li, Yan-Rong Li, Zhiyuan Lindqvist, Michael Lico, Rocco Astronomy Department University of Arizona 933 N. Cherry Ave TucsonAZ85721 United States Department of Physics University of Arizona 1118 E 4th St TucsonAZ85721 United States School of Natural Sciences Institute for Advanced Study 1 Einstein Drive PrincetonNJ08540 United States Black Hole Initiative at Harvard University 20 Garden Street CambridgeMA02138 United States Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Illinois Center for Advanced Studies of the Universe Department of Physics University of Illinois 1110 West Green Street UrbanaIL61801 United States Department of Astronomy University of Illinois 1002 West Green Street UrbanaIL61801 United States Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road WestfordMA01886 United States National Astronomical Observatory of Japan 2-21-1 Osawa Tokyo Mitaka181-8588 Japan Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n GranadaE-18008 Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Department of Physics Faculty of Science University of Malaya Kuala Lumpur50603 Malaysia Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Departament d’Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 València BurjassotE-46100 Spain Observatori Astronòmic Universitat de València C. Catedrático José Beltrán 2 València PaternaE-46980 Spain Steward Observatory and Department of Astronomy University of Arizona 933 N. Cherry Ave. TucsonAZ85721 United States Fermi National Accelerator Laboratory MS209 P.O. Box 500 BataviaIL60510 United States Department of Astronomy and Astrophysics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States East Asian Observatory 660 N. A’ohoku Place HiloHI96720 United States PO Box 9513 Leiden2

The black-hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5–61 days) is comparable to the 6-day extent of the 2017 EHT observations. Closure phases along baseline triangles are robust interferometric observables that are sensitive to the expected structural changes of the images but are free of station-based atmospheric and instrumental errors. We explored the day-to-day variability in closure phase measurements on all six linearly independent non-trivial baseline triangles that can be formed from the 2017 observations. We showed that three triangles exhibit very low day-to-day variability, with a dispersion of ∼ 3 − 5◦. The only triangles that exhibit substantially higher variability (∼ 90 − 180◦) are the ones with baselines that cross visibility amplitude minima on the u − v plane, as expected from theoretical modeling. We used two sets of General Relativistic magnetohydrodynamic simulations to explore the dependence of the predicted variability on various black-hole and accretion-flow parameters. We found that changing the magnetic field configuration, electron temperature model, or black-hole spin has a marginal effect on the model consistency with the observed level of variability. On the other hand, the most discriminating image characteristic of models is the fractional width of the bright ring of emission. Models that best reproduce the observed small level of variability are characterized by thin ring-like images with structures dominated by gravitational lensing effects and thus least affected by turbulence in the accreting plasmas. Copyright © 2021, The Authors. All rights reserved.

关键词： Stars

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Long-term multi-wavelength study of 1ES 0647+250

arXiv

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arXiv 2022年

作者： Acciari, MAGIC Collaboration V.A. Aniello, T. Ansoldi, S. Antonelli, L.A. Arbet Engels, A. Arcaro, C. Artero, M. Asano, K. Baack, D. Babić, A. Baquero, A. Barres de Almeida, U. Barrio, J.A. Batković, I. Becerra González, J. Bednarek, W. Bernardini, E. Bernardos, M. Berti, A. Besenrieder, J. Bhattacharyya, W. Bigongiari, C. Biland, A. Blanch, O. Bökenkamp, H. Bonnoli, G. Bošnjak, Ž. Burelli, I. Busetto, G. Carosi, R. Carretero-Castrillo, M. Ceribella, G. Chai, Y. Chilingarian, A. Cikota, S. Colombo, E. Contreras, J.L. 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, R.J. Garczarczyk, M. Gasparyan, S. Gaug, M. Giesbrecht Paiva, J.G. Giglietto, N. Giordano, F. Gliwny, P. Godinović, N. Green, J.G. Green, D. Hadasch, D. Hahn, A. Hassan, T. Heckmann, L. Herrera, J. Hrupec, D. Hütten, M. Inada, T. Iotov, R. Ishio, K. Iwamura, Y. 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. 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, J.M. Mirzoyan, R. Molina, E. Mondal, H.A. 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, J.M. Pavletić, L. Instituto de Astrofísica de Canarias Dpto. de Astrofísica Universidad de La Laguna La LagunaE-38200 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik MünchenD-80805 Germany Università di Padova INFN PadovaI-35131 Italy Bellaterra BarcelonaE-08193 Spain The University of Tokyo Chiba Kashiwa277-8582 Japan Technische Universität Dortmund DortmundD-44221 Germany Zagreb10000 Croatia IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain URCA RJ Rio de Janeiro22290-180 Brazil University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain ZeuthenD-15738 Germany ETH Zürich ZürichCH-8093 Switzerland Università di Pisa INFN Pisa PisaI-56126 Italy Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Armenian MAGIC Group A. Alikhanyan National Science Laboratory Yerevan0036 Armenia Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain Department for Physics and Technology University of Bergen Norway INFN MAGIC Group INFN Sezione di Catania Dipartimento di Fisica e Astronomia University of Catania CataniaI-95123 Italy INFN MAGIC Group INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy INFN MAGIC Group INFN Sezione di Bari Dipartimento Interateneo di Fisica dell’Università e del Politecnico di Bari BariI-70125 Italy Croatian MAGIC Group University of Rijeka Department of Physics Rijeka51000 Croatia Universität Würzburg WürzburgD-97074 Germany University of Geneva Chemin d’Ecogia 16 VersoixCH-1290 Switzerland Finnish MAGIC Group Finnish Centre for Astronomy with ESO University of Turku TurkuFI-20014 Finland Departament de Física CERES-IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Japanese MAGIC Grou

Context. The BL Lac object 1ES 0647+250 is one of the few distant γ-ray emitting blazars detected at very high energies (VHEs;&100 GeV) during a non-flaring state. It was detected with the MAGIC telescopes during a period of low activity in the years 2009-2011 as well as during three flaring activities in the years 2014, 2019, and 2020, with the highest VHE flux in the last epoch. An extensive multi-instrument data set was collected as part of several coordinated observing campaigns over these years. Aims. We aim to characterise the long-term multi-band flux variability of 1ES 0647+250, as well as its broadband spectral energy distribution (SED) during four distinct activity states selected in four different epochs, in order to constrain the physical parameters of the blazar emission region under certain assumptions. Methods. We evaluated the variability and correlation of the emission in the different energy bands with the fractional variability and the Z-transformed discrete correlation function, as well as its spectral evolution in X-rays and γ rays. Owing to the controversy in the redshift measurements of 1ES 0647+250 reported in the literature, we also estimated its distance in an indirect manner through a comparison of the GeV and TeV spectra from simultaneous observations with Fermi-LAT and MAGIC during the strongest flaring activity detected to date. Moreover, we interpret the SEDs from the four distinct activity states within the framework of one-component and two-component leptonic models, proposing specific scenarios that are able to reproduce the available multi-instrument data. Results. We find significant long-term variability, especially in X-rays and VHE γ rays. Furthermore, significant (3-4σ) correlations were found between the radio, optical, and high-energy (HE) γ-ray fluxes, with the radio emission delayed by about ∼400 days with respect to the optical and γ-ray bands. The spectral analysis reveals a harder-when-brighter trend during the non-flar

关键词： Gamma rays

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Circumbinary planet study around NSVS 14256825

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Journal of Physics: Conference Series 2019年第1期1380卷

作者： P Sappankum S Komonjinda S Awiphan R Rattanamala V S Dhillon T R Marsh S Suphapolthaworn Master of Science Program in Astronomy Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand National Astronomical Research Institute of Thailand (Public Organization) 260 Moo 4 Donkaew Mae Rim Chiang Mai 50180 Thailand Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand PhD Program in Astronomy Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Department of Physics and General Science Faculty of Science and Technology Nakhon Ratchasima Rajabhat University Nakhon Ratchasima 30000 Thailand Department of Physics and Astronomy University of Sheffield Sheffield S3 7RH UK Department of Physics University of Warwick Coventry CV4 7AL UK Department of Physics School of Science Hokkaido University Sapporo Hokkaido 060-0808 Japan

The period variability of (O-C) diagram of an eclipsing binary, NSVS 14256825, which is composed of a hot subdwarf type OB star (sdOB) and a main-sequence low-mass type M star (dM) in close orbit with period P=0.110374 days, previously showed sinusoidal signal cause by the light travel time effects. This signal can be caused by the presence of third bodies. We re-examined (O-C) diagram of the system. We combined eclipse timings from published data and the data taken from ULTRASPEC at 2.4 m at Thai national Telescope on November 2018. From the fitting model, the parameters of the third body in NSVS 14256825 system are obtained.

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