Multiwavelength observations of the blazar BL Lacertae: a new fast TeV gamma-ray flare

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Journal ISSN
Volume Title
A4 Artikkeli konferenssijulkaisussa
Date
2017
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Degree programme
Language
en
Pages
8
Series
35th International Cosmic Ray Conference, ICRC2017. The astroparticle physics conference. 12-20 July 2017, Bexco, Busan, Korea, Pos proceedings of science
Abstract
Observations of fast TeV $\gamma$-ray flares from blazars reveal the extreme compactness of emitting regions in blazar jets. Combined with very-long-baseline radio interferometry measurements, they probe the structure and emission mechanism of the jet. We report on a fast TeV $\gamma$-ray flare from BL Lacertae observed by VERITAS, with a rise time of about 2.3 hours and a decay time of about 36 minutes. The peak flux at $>$200 GeV measured with the 4-minute binned light curve is $(4.2 \pm 0.6) \times 10^{-6} \;\text{photons} \;\text{m}^{-2}\, \text{s}^{-1}$, or $\sim$180% the Crab Nebula flux. Variability in GeV $\gamma$-ray, X-ray, and optical flux, as well as in optical and radio polarization was observed around the time of the TeV $\gamma$-ray flare. A possible superluminal knot was identified in the VLBA observations at 43 GHz. The flare constrains the size of the emitting region, and is consistent with several theoretical models with stationary shocks.
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Keywords
Astrophysics - High Energy Astrophysical Phenomena, 115 Astronomy and space science
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Citation
Feng , Q , Jorstad , S G , Marscher , A P , Lister , M L , Kovalev , Y Y , Pushkarev , A B , Savolainen , T , Agudo , I , Molina , S N , Gomez , J L , Larionov , V M , Borman , G A , Mokrushina , A A & Smith , P S 2017 , Multiwavelength observations of the blazar BL Lacertae: a new fast TeV gamma-ray flare . in 35th International Cosmic Ray Conference, ICRC2017. The astroparticle physics conference. 12-20 July 2017, Bexco, Busan, Korea . Pos proceedings of science , Sissa , Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017) , International Cosmic Ray Conference , Busan , Korea, Republic of , 10/07/2017 .