Dynamic changes of emitting electron distribution in the jet of 3C 279: signatures of acceleration and cooling
Abstract
We study the dynamic changes of electron energy distribution (EED) through systematically analysing the quasisimultaneous spectral energy distributions (SEDs) of the flat spectrum radio quasar 3C 279 in different states. With Markov chain Monte Carlo technique we model fourteen SEDs of 3C 279 using a leptonic model with a threeparameter logparabola EED. The 14 SEDs can be satisfactorily fitted with the onezone leptonic model. The observed γ rays in 13 states are attributed to Compton scattering of external infrared photons from a surrounding dusty torus. The curved γ ray spectrum observed during 2014 28 April is well explained by the external Compton of dust radiation. It is found that there is a clear positive correlation between the curvature parameter b of the EED and the electron peak energy γ ^' }_pk. No significant correlation between b and the synchrotron peak frequency ν_{s} is found, due to the varied product of Doppler factor and fluid magnetic field from state to state. We interpret the correlation of bγ ^' }_pk in a stochastic acceleration scenario. This positive correlation is in agreement with the prediction in the stage when the balance between acceleration and radiative cooling of the electrons is nearly established in the case of the turbulence spectral index q = 2.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 February 2016
 DOI:
 10.1093/mnras/stv2829
 arXiv:
 arXiv:1510.03118
 Bibcode:
 2016MNRAS.456.2173Y
 Keywords:

 radiation mechanisms: nonthermal;
 galaxies: jets;
 gamma rays: galaxies;
 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 Accepted by MNRAS