Issue |
A&A
Volume 638, June 2020
|
|
---|---|---|
Article Number | A14 | |
Number of page(s) | 16 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/201935450 | |
Published online | 03 June 2020 |
Broadband characterisation of the very intense TeV flares of the blazar 1ES 1959+650 in 2016
1
Inst. de Astrofísica de Canarias, 38200 La Laguna, Spain
2
Universidad de La Laguna, Dpto. Astrofísica, 38206 La Laguna, Tenerife, Spain
3
Università di Udine, and INFN Trieste, 33100 Udine, Italy
4
National Institute for Astrophysics (INAF), 00136 Rome, Italy
5
ETH Zurich, 8093 Zurich, Switzerland
6
Technische Universität Dortmund, 44221 Dortmund, Germany
7
Croatian Consortium: University of Rijeka, Department of Physics, 51000 Rijeka; University of Split – FESB, 21000 Split; University of Zagreb – FER, 10000 Zagreb; University of Osijek, 31000 Osijek; Rudjer Boskovic Institute, 10000 Zagreb, Croatia
8
Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Salt Lake, Sector-1, Kolkata 700064, India
9
Centro Brasileiro de Pesquisas Físicas (CBPF), 22290-180 URCA, Rio de Janeiro, RJ, Brasil
10
Unidad de Partículas y Cosmología (UPARCOS), Universidad Complutense, 28040 Madrid, Spain
11
University of Łódź, Department of Astrophysics, 90236 Łódź, Poland
12
Università di Siena and INFN Pisa, 53100 Siena, Italy
13
Deutsches Elektronen-Synchrotron (DESY), 15738 Zeuthen, Germany
14
Istituto Nazionale Fisica Nucleare (INFN), 00044 Frascati, Roma, Italy
15
Max-Planck-Institut für Physik, 80805 München, Germany
16
Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology (BIST), 08193 Bellaterra, Barcelona, Spain
17
Università di Padova and INFN, 35131 Padova, Italy
18
Università di Pisa, and INFN Pisa, 56126 Pisa, Italy
19
Universität Würzburg, 97074 Würzburg, Germany
20
Finnish MAGIC Consortium: Tuorla Observatory (Department of Physics and Astronomy) and Finnish Centre of Astronomy with ESO (FINCA), University of Turku, 20014 Turku, Finland; Astronomy Division, University of Oulu, 90014 Oulu, Finland
21
Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
22
Japanese MAGIC Consortium: ICRR, The University of Tokyo, 277-8582 Chiba, Japan; Department of Physics, Kyoto University, 606-8502 Kyoto, Japan; Tokai University, 259-1292 Kanagawa, Japan; RIKEN, 351-0198 Saitama, Japan
23
ICRANet-Armenia at NAS RA, 0019 Yerevan, Armenia
24
Inst. for Nucl. Research and Nucl. Energy, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria
25
Universitat de Barcelona, ICCUB, IEEC-UB, 08028 Barcelona, Spain
26
Humboldt University of Berlin, Institut für Physik, 12489 Berlin, Germany
27
Dipartimento di Fisica, Università di Trieste, 34127 Trieste, Italy
28
Port d’Informació Científica (PIC), 08193 Bellaterra, Barcelona, Spain
29
INAF-Trieste and Dept. of Physics & Astronomy, University of Bologna, Bologna, Italy
30
Department of Physics, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
Received:
12
March
2019
Accepted:
16
January
2020
1ES 1959+650 is a bright TeV high-frequency-peaked BL Lac object exhibiting interesting features like “orphan” TeV flares and broad emission in the high-energy regime that are difficult to interpret using conventional one-zone Synchrotron Self-Compton (SSC) scenarios. We report the results from the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) observations in 2016 along with the multi-wavelength data from the Fermi Large Area Telescope (LAT) and Swift instruments. MAGIC observed 1ES 1959+650 with different emission levels in the very-high-energy (VHE, E > 100 GeV) γ-ray band during 2016. In the long-term data, the X-ray spectrum becomes harder with increasing flux and a hint of a similar trend is also visible in the VHE band. An exceptionally high VHE flux reaching ∼3 times the Crab Nebula flux was measured by MAGIC on the 13 and 14 of June, and 1 July 2016 (the highest flux observed since 2002). During these flares, the high-energy peak of the spectral energy distribution (SED) lies in the VHE domain and extends up to several TeV. The spectrum in the γ-ray (both Fermi-LAT and VHE bands) and the X-ray bands are quite hard. On 13 June and 1 July 2016, the source showed rapid variations in the VHE flux within timescales of less than an hour. A simple one-zone SSC model can describe the data during the flares requiring moderate to large values of the Doppler factors (δ ≥ 30−60). Alternatively, the high-energy peak of the SED can be explained by a purely hadronic model attributed to proton-synchrotron radiation with jet power Ljet ∼ 1046 erg s−1 and under high values of the magnetic field strength (∼100 G) and maximum proton energy (∼few EeV). Mixed lepto-hadronic models require super-Eddington values of the jet power. We conclude that it is difficult to get detectable neutrino emission from the source during the extreme VHE flaring period of 2016.
Key words: astroparticle physics / BL Lacertae objects: individual: 1ES 1959+650 / galaxies: jets / methods: observational / radiation mechanisms: non-thermal / neutrinos
© ESO 2020
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