First detection of VHE gamma-ray emission from TXS 1515-273, study of its X-ray variability and spectral energy distribution



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Baquero Larriva, Orlando Andrés and Barrio Uña, Juan Abel and Contreras González, José Luis and Fonseca González, Mª Victoria and Hoang, Kim Dinh and López Moya, Marcos and Miener, Tjark and Morcuende, D. and Peñil del Campo, Pablo and Saha, Lab and otros, ... (2021) First detection of VHE gamma-ray emission from TXS 1515-273, study of its X-ray variability and spectral energy distribution. Monthly notices of the Royal Astronomical Society, 507 (1). pp. 1528-1545. ISSN 0035-8711

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We report here on the first multiwavelength (MWL) campaign on the blazar TXS 1515-273, undertaken in 2019 and extending from radio to very-high-energy gamma-rays (VFW). Up until now, this blazar had not been the subject of any detailed MWL observations. It has a rather hard photon index at GeV energies and was considered a candidate extreme high-synchrotron-peaked source. MAGIC observations resulted in the first-time detection of the source in VHE with a statistical significance of 7.6 sigma. The average integral VHE flux of the source is 6 +/- 1 per cent of the Crab nebula flux above 400 GeV. X-ray coverage was provided by Swift-XRT, XMM-Newton, and NuSTAR. The long continuous X-ray observations were separated by similar to 9 h, both showing clear hour scale flares. In the XMM-Newton data, both the rise and decay time-scales are longer in the soft X-ray than in the hard X-ray band, indicating the presence of a particle cooling regime. The X-ray variability time-scales were used to constrain the size of the emission region and the strength of the magnetic field. The data allowed us to determine the synchrotron peak frequency and classify the source as a flaring high, but not extreme synchrotron-peaked object. Considering the constraints and variability patterns from the X-ray data, we model the broad-band spectral energy distribution. We applied a simple one-zone model, which could not reproduce the radio emission and the shape of the optical emission, and a two-component leptonic model with two interacting components, enabling us to reproduce the emission from radio to VHE band.

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Artículo firmado por 197 autores. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. We would like to thank the Instituto de Astrofisica 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 ERDF under the Spanish Ministerio de Ciencia e Innovacion (MICINN) (FPA201787859-P, FPA2017-85668-P, FPA2017-82729-C6-5-R, FPA201790566-REDC, PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-105510GB-C31, PID2019-107847RB-C41, PID2019107847RB-C42, PID2019-107847RB-C44, PID2019-107988GBC22); 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 DO1268/16.12.2019 and the Academy of Finland grant nr. 317637 and 320045 are gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia `Severo Ochoa' SEV-20160588, SEV-2017-0709 and CEX2019-000920-S, and `Maria de Maeztu' CEX2019-000918-M, the Unidad de Excelencia `Maria de Maeztu' MDM-2015-0509-18-2 and the `la Caixa' Foundation (fellowshipLCF/BQ/PI18/11630012), by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq, and FAPERJ.; The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, theCommissariat `a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase from the following agencies is also gratefully acknowledged: the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Etudes Spatiales in France.; This research has made use of data and/or software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC. This research has made use of data from the MOJAVE data base that is maintained by the MOJAVE team (Lister et al. 2018).

Uncontrolled Keywords:Large-area telescope; Bl-lac objects; Active galactic nuclei; Photon imaging camera; Complete sample; Tev blazars; Neutrino emission; Magic telescopes; 3rd catalog; 2nd catalog
Subjects:Sciences > Physics > Nuclear physics
ID Code:68678
Deposited On:11 Nov 2021 11:52
Last Modified:15 Nov 2021 11:42

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