A4 Refereed article in a conference publication
TeV detection and insights into the emission regions of two gamma-ray fast flaring blazars
Authors: Cerasole, Davide; Di Venere, Leonardo; Giordano, Fransesco; Lindfors Elina; Loporchio S.; Pavletic Lovro; on behalf of the MAGIC and Fermi-LAT Collaborations
Editors: Aramo, Carla; Buscemi, Mario; Caruso, Rossella; Colalillo, Roberta; Leonora, Emanuele; Mallamaci, Manuela; Scotti, Valentina; Valore, Laura
Conference name: Cosmic-Ray International Studies and Multi-Messenger Astroparticle Conference
Publisher: IOP Publishing
Publication year: 2025
Journal:: Journal of Physics: Conference Series
Book title : 13th Cosmic-Ray International Studies and Multi-messenger Astroparticle Conference 17/06/2024 - 21/06/2024 Trapani, Italy
Article number: 012019
Volume: 3053
ISSN: 1742-6588
eISSN: 1742-6596
DOI: https://doi.org/10.1088/1742-6596/3053/1/012019
Web address : https://doi.org/10.1088/1742-6596/3053/1/012019
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/500366915
The γ-ray blazars B2 1811+31 and GB6 J1058+2817 exhibited strong flaring activity in 2020 and 2021, respectively. These high states were observed by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope in the high-energy (HE; 100 MeV < E < 100 GeV) γ-ray band, triggering observations in the very-high-energy (VHE, E > 100 GeV) γ-ray band with the MAGIC telescopes, in UV and X rays with the Neil Gehrels Swift Observatory and in the radio and optical bands with many ground-based telescopes. MAGIC telescopes observations led to the first detection at VHE of both sources. In this contribution, we present the details of these detections and the results of an extensive study of the high-state properties of the two blazars. Fermi-LAT data were used to derive long-term γ-ray light-curves and identify the periods of enhanced activity in both sources. We investigated their spectral properties and temporal variability, with focus on how the strong spectral hardening and the variability timescale can provide information on the γ-ray emitting regions during the flare.
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Funding information in the publication:
We would like to thank the Instituto de Astrof´ısica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF, MPG and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the grants PID2019- 104114RB-C31, PID2019-104114RB-C32, PID2019-104114RB-C33, PID2019-05510GB-C31, PID2019- 107847RB-C41, PID2019-107847RB-C42, PID2019-107847RB-C44, PID2019-107988GB-C22 funded by MCIN/AEI/ 10.13039/501100011033; the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-400/18.12.2020 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also been supported by Centros de Excelencia “Severo Ochoa” y Unidades “Mar´ıa de Maeztu” program of the MCIN/AEI/ 10.13039/501100011033 (SEV-2016-0588, SEV-2017- 0709, CEX2019-000920-S, CEX2019-000918-M, MDM-2015-0509-18-2) and by the CERCA institution of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project uniri-prirod-18-48; by the Deutsche Forschungsgemeinschaft (SFB1491 and SFB876); the Polish Ministry Of Education and Science grant No. 2021/WK/08; and by the Brazilian MCTIC, CNPq and FAPERJ. The Fermi-LAT Collaboration acknowledges support for LAT development, operation and data analysis from NASA and DOE (United States), CEA/Irfu and IN2P3/CNRS (France), ASI and INFN (Italy), MEXT, KEK, and JAXA (Japan), and the K.A. Wallenberg Foundation, the Swedish Research Council and the National Space Board (Sweden). Science analysis support in the operations phase from INAF (Italy) and CNES (France) is also gratefully acknowledged. This work performed in part under DOE Contract DE-AC02-76SF00515.
