Talk detail

Participant	Hayashida, Masaaki
Institution	Institute Cosmic-Ray Research, the University of Tokyo - 5-1-5 Kashiwanoha - Kashiwa - Chiba - Japan

Session	GN2	Accepted		Order	Time
Talk	Oral abstract	Title	Multi-wavelength observations of blazar 3C 279 during flaring states in 2013-2014 and a stochastic electron acceleration model
Coauthors
Abstract	New multi-wavelength observing campaign in gamma-ray to radio bands on a flat spectrum radio quasar (FSRQ) 3C 279 was carried out during a phase of increased activity from 2013 December to 2014 April, including first observations of it with NuSTAR. The gamma-ray emission of the source showed multiple distinct flares reaching the highest flux level measured in this object since the beginning of the Fermi mission, with an integrated flux above 100 MeV of ~10^-5 ph cm-2 s-1, and with a flux doubling time scale as short as 2 hours. The gamma-ray spectrum during one of the flares was very hard, with an index of 1.7, which is rarely seen in FSRQs. The lack of concurrent optical variability implies a very high Compton dominance parameter. The rapid variability suggests the location of the gamma-ray emitting region is comparable with the broad line region radius. In order to reproduce the observed hard photon index by inverse-Compton scattering in the fast cooling regime, we consider a stochastic electron acceleration model because a normal shock acceleration process can hardly generate the hard index of parent electrons, which should be much harder than 2. In this contribution, new results of our multi-wavelength observations for 3C 279 during the flaring states will be presented in detail. The emission model as well as our first application of the stochastic acceleration model for the observed gamma-ray flare in the FSRQ will be discussed.
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