First detection of VHE gamma-ray signal from the FSRQ TON 0599

ABSTRACT TON 0599 (z = 0.7247) belongs to the few flat spectrum radio quasars (FSRQs) detected in the very high energy (VHE, $E > 100$ GeV) gamma-ray band. Its redshift makes it currently one of the farthest VHE gamma-ray sources. It was detected for the first time with the MAGIC telescopes on 2017 December 15, and observed until December 29. The flux reached a maximum of about 50 per cent of the Crab Nebula flux above 80 GeV on the second night of observation, after which we witnessed a gradual decrease of the flux. The VHE gamma-ray spectrum connects smoothly to the one in the high energy ($E > 100$ MeV) band obtained from simultaneous observations with Fermi-LAT. It features a cut-off at energies around 50 GeV, indicating the location of the gamma-ray emission zone beyond the broad line region. In addition, we were able to follow the spectral evolution during the fading phase of the flare. Multiwavelength analysis based on observations in optical, near-infrared, and radio bands acquired by the Whole Earth Blazar Telescope Collaboration from November to March, as well as observations in X-ray and optical–UV bands with instruments on board the Swift satellite, shows strong correlation between different bands. We model the broadband emission with a simple one-zone leptonic model, where the high-energy peak is predominantly produced by external Compton scattering of photons from the dusty torus.

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Journal
Monthly Notices of the Royal Astronomical Society
Published
2026-01-12
DOI
https://doi.org/10.1093/mnras/stag032
Citations
1
Primary Topic
Astrophysics and Cosmic Phenomena
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article
Field-Weighted Citation Impact
27.96
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article

First detection of VHE gamma-ray signal from the FSRQ TON 0599

M. Persic, Mattia Doro, Alvaro Mas-Aguilar, Laura Eisenberger et al.
1 citations
Monthly Notices of the Royal Astronomical Society
Astrophysics and Cosmic Phenomena
27.96
article

First detection of VHE gamma-ray signal from the FSRQ TON 0599

M. Persic, Mattia Doro, Alvaro Mas-Aguilar, Laura Eisenberger, E. Bernardini, M. Carretero-Castrillo, Włodzimierz Bednarek, D. Mazin, D. Israyelyan, J. Delgado, Lea Heckmann, E. Lindfors, S. Lombardi, J. Escudero, A. Hahn, Francesco Di Pierro, Davide Cerasole, A. Okumura, Julius Konrad, Yating Chai, M. Khachatryan, Jayant Abhir, E. Bronzini, A. Campoy-Ordaz, S. Kankkunen, Martin MAKARIEV, S. Mangano, R. Di Tria, R. Mirzoyan, Alessio Berti, Markus Garczarczyk, Stefano Ansoldi, D. Hadasch, K. Nilsson, K. Abe, Enrique Carrasco Molina, Takeshi Nakamori, Adhitiya Dinesh, Junko Kushida, D. Kerszberg, A De Angelis, P Maruševec, S Mender, A Abhishek, R Takeishi, S Fröse, P M Kouch, S Abe, J Becerra González, A Arbet Engels, M López-Moya, D Dominis Prester, H E Jermak, M K Hallum, J G Green, A Biland, J G Giesbrecht Paiva, P Da Vela, M Manganaro, I Agudo, P Günther, C Nigro, R de Menezes, J Jormanainen, I Jiménez Martínez, S Nozaki, A Carosi, L Font, P Majumdar, G D’Amico, F Dazzi, S Menchiari, T Gradetzke, M Gaug, K Mannheim, T Hassan, M Delfino, L Nikolić, V Neustroev, Y Fukazawa, F Giordano, Ž Bošnjak, M Peresano, L Foffano, K Asano, D Miceli, C Delgado Mendez, J Bernete, R Imazawa, L Barrios-Jiménez, J L Contreras, A Moralejo, J Jiménez Quiles, U Barres de Almeida, A Aguasca-Cabot, G A Borman, J Besenrieder, C Nanci, S O Kurtanidze, S Gasparyan, S Fukami, A Donini, J Herrera Llorente, Y Ohtani, C Bigongiari, T Terzić, K Nishijima, O Blanch, H A Mondal, C Righi, D Dorner, M Molero González, M Pihet, M Martínez, F Longo, C Arcaro, L V Larionova, A Babić, S Covino, L A Antonelli, D Green, W P Chen, V A Acciari, R López-Coto, M Láinez, G Maneva, B De Lotto, R Carosi, A Cifuentes, K Noda, A López-Oramas, A Lorini, I Burelli, N Godinović, D Hrupec, G Bonnoli, I S Troitskiy, L Lulić, E Lyard, V M Larionov, J Baxter, R Grau, J Cortina, A J Castro-Tirado, T Aniello, P Gliwny, D Elsaesser, J M Miranda, M Mariotti, S Loporchio, G Ceribella, L Nickel, A Lamastra, H Kubo, J A Barrio, Z R Weaver
article en
1 citations

Abstract

ABSTRACT TON 0599 (z = 0.7247) belongs to the few flat spectrum radio quasars (FSRQs) detected in the very high energy (VHE, $E > 100$ GeV) gamma-ray band. Its redshift makes it currently one of the farthest VHE gamma-ray sources. It was detected for the first time with the MAGIC telescopes on 2017 December 15, and observed until December 29. The flux reached a maximum of about 50 per cent of the Crab Nebula flux above 80 GeV on the second night of observation, after which we witnessed a gradual decrease of the flux. The VHE gamma-ray spectrum connects smoothly to the one in the high energy ($E > 100$ MeV) band obtained from simultaneous observations with Fermi-LAT. It features a cut-off at energies around 50 GeV, indicating the location of the gamma-ray emission zone beyond the broad line region. In addition, we were able to follow the spectral evolution during the fading phase of the flare. Multiwavelength analysis based on observations in optical, near-infrared, and radio bands acquired by the Whole Earth Blazar Telescope Collaboration from November to March, as well as observations in X-ray and optical–UV bands with instruments on board the Swift satellite, shows strong correlation between different bands. We model the broadband emission with a simple one-zone leptonic model, where the high-energy peak is predominantly produced by external Compton scattering of photons from the dusty torus.

Monthly Notices of the Royal Astronomical SocietyVol. 546(4)
University of Siena (IT), University of Pisa (IT), Boston University (US), Yamagata University (JP), Hiroshima University (JP), University of Geneva (CH), University of Insubria (IT), Obayashi (Japan) (JP), Universidad Complutense de Madrid (ES), Universitat Autònoma de Barcelona (ES), Texas Tech University (US), Centre National de la Recherche Scientifique (FR), Ceres (US), Tokai University (JP), University of Denver (US), University of Arizona (US), University of Padua (IT), University of Trieste (IT), University of Rijeka (HR), Universidad de La Laguna (ES), Chiba University (JP), Konan University (JP), Saha Institute of Nuclear Physics (IN), St Petersburg University (RU), International Research Center for Japanese Studies (JP), University of Zagreb (HR), Turku Centre for Computer Science (FI), Al-Farabi Kazakh National University (KZ), Institute for High Energy Physics (ES), Homi Bhabha National Institute (IN), TU Dortmund University (DE), Aarhus University (DK), Université Paris Cité (FR), National Central University (TW), Kyoto University (JP), Heidelberg University (DE), Bulgarian Academy of Sciences (BG), University of Würzburg (DE), Pulkovo Observatory (RU), Fesenkov Astrophysical Institute (KZ), Deutsches Elektronen-Synchrotron DESY (DE), Laboratoire AstroParticule et Cosmologie (FR), Evgeni Kharadze Georgian National Astrophysical Observatory (GE), University of Łódź (PL), ETH Zurich (CH), Max Planck Institute for Physics (DE), Istituto Nazionale di Fisica Nucleare, Sezione di Torino (IT), Institute for Space Astrophysics and Planetology (IT), Ulugh Beg Astronomical Institute (UZ), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (IT), Osservatorio Astrofisico di Torino (IT), Max Planck Institute for Astronomy (DE), Istituto Nazionale di Fisica Nucleare, Sezione di Bari (IT), Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata (IT), Istituto di Radioastronomia di Bologna (IT), Ladies College (LK), National Center of Space Research and Technology (KZ), Institute of Astronomy and National Astronomical Observatory (BG), Finnish Youth Research Society (FI), International Center for Relativistic Astrophysics (IT), Center for Astrophysics Harvard & Smithsonian (US), Centro Brasileiro de Pesquisas Físicas (BR), Nordic Optical Telescope (ES), Instituto de Astrofísica de Canarias (ES), Metsähallitus (Finland) (FI), International Center for Relativistic Astrophysics Network (AM), Port d'Informació Científica (ES), Instituto de Radioastronomía Milimétrica (ES), GFZ Helmholtz Centre for Geosciences (DE), Astronomical Observatory (RS), Istituto Nazionale di Fisica Nucleare, Sezione di Roma I (IT), Max Planck Institute for Radio Astronomy (DE), Instituto de Astrofísica de Andalucía (ES), Telescopio Nazionale Galileo (ES), Istituto Nazionale di Fisica Nucleare, Sezione di Pisa (IT), Crimean Astrophysical Observatory (UA), Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES), Institute of Science and Technology, University of Bergen (NO), National University of Uzbekistan (UZ), University of Osijek (HR), University of Turin (IT), Sofia University "St. Kliment Ohridski" (BG), Nagoya University (JP), Liverpool John Moores University (GB), Polytechnic University of Bari (IT), Universitat de Barcelona (ES), The University of Tokyo (JP), National Institute for Astrophysics (IT), Foundation for Research and Technology Hellas (GR), University of Colorado Denver (US), University of Split (HR), University of Oulu (FI), Aalto University (FI)
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