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Title: Multi-wavelength study of flaring activity in BL Lac object S5 0716+714 during the 2015 outburst

We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of 2015 January. Observed almost simultaneously in the optical, X-rays, and γ-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A TeV (VHE) detection was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about five days apart, were seen in almost all of the energy bands. The multi-wavelength light curves, spectral energy distribution, and polarization are modeled using the time-dependent code developed by Zhang et al. This model assumes a straight jet threaded by large-scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. Furthermore, the rapid variation in PD and rotation in PA are most likely due to reconnections happening in the emission region in the jet, as suggested by the change in the ratio of toroidal to poloidal components of the magnetic field during the quiescent and flaring states.
 [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [4] ;  [4]
  1. Tata Institute of Fundamental Research, Mumbai (India)
  2. Ohio Univ., Athens, OH (United States); ; Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. North-West Univ., Potchefstroom (South Africa)
  4. Physical Research Lab., Ahmedabad (India)
Publication Date:
Report Number(s):
Journal ID: ISSN 1538-4357
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 809; Journal Issue: 2; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; BL Lacertae objects: individual (S5 0716+714)
OSTI Identifier: