Magnetic Field Amplification and Blazar Flares

Abstract

Recent multiwavelength observations of PKS 0208-512 by SMARTS, Fermi, and Swift revealed that gamma-ray and optical light curves of this flat spectrum radio quasars are highly correlated, but with an exception of one large optical flare having no corresponding gamma-ray activity or even detection. On the other hand, recent advances in SNRs observations and plasma simulations both reveal that magnetic field downstream of astrophysical shocks can be largely amplified beyond simple shock compression. These amplifications, along with their associated particle acceleration, might contribute to blazar flares, including the peculiar flare of PKS 0208-512. Using our time dependent multizone blazar emission code, we evaluate several scenarios that may represent such phenomena. This code combines Monte Carlo method that tracks the radiative processes including inverse Compton scattering, and Fokker-Planck equation that follows the cooling and acceleration of particles. It is a comprehensive time dependent code that fully takes into account the light travel time effects. In this study, both the changes of the magnetic field and acceleration efficiency are explored as the cause of blazar flares. Under these assumption, synchrotron self-Compton and external Compton scenarios produce distinct features that favor the external Compton scenario. The optical flares with/without gamma-ray counterparts can be explained by different allocations of energy between the magnetization and particle acceleration, which in turn can be affected by the relative orientation between the magnetic field and the shock flow. We compare the details of the observations and simulation, and highlight what implications this study has on our understanding of relativistic jets.

6 pages. To appear in the proceeding of 'The Innermost Regions of Relativistic Jets and Their Magnetic Fields', Granada, Spain

References in corpus (8)

• Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?
• MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21
• Observational constraints on energetic particle diffusion in young SNRs: amplified magnetic field and maximum energy
• Stochastic particle acceleration and synchrotron self--Compton radiation in TeV blazars
• H.E.S.S. discovery of VHE gamma-rays from the quasar PKS 1510-089
• The Firm Redshift Lower Limit of the Most Distant TeV-Detected Blazar PKS 1424+240
• Turbulent amplification of magnetic field driven by dynamo effect at rippled shocks
• Implications of the Anomalous Outburst in the Blazar PKS 0208-512

Cited by in corpus (2)

• Constraining the Physical Conditions in the Jets of Gamma-Ray Flaring Blazars using Centimeter-Band Polarimetry and Radiative Transfer Simulations. I. Data and Models for 0420-014, OJ 287, and 1156+295
• Leptonic and Lepto-Hadronic Modeling of the Nov. 2010 flare from 3C 454.3