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Probing Acceleration and Turbulence at Relativistic Shocks in Blazar JetsDiffusive shock acceleration (DSA) at relativistic shocks is widely thought to be an important acceleration mechanism in various astrophysical jet sources, including radio-loud active galactic nuclei such as blazars. Such acceleration can produce the non-thermal particles that emit the broad-band continuum radiation that is detected from extragalactic jets. An important recent development for blazar science is the ability of Fermi-Large Area Telescope spectroscopy to pin down the shape of the distribution of the underlying non-thermal particle population. This paper highlights how multiwavelength spectra spanning optical to X-ray to gamma-ray bands can be used to probe diffusive acceleration in relativistic, oblique, magnetohydrodynamic (MHD) shocks in blazar jets. Diagnostics on the MHD turbulence near such shocks are obtained using thermal and non-thermal particle distributions resulting from detailed Monte Carlo simulations of DSA. These probes are afforded by the characteristic property that the synchrotron vF(sub v), peak energy does not appear in the gamma-ray band above 100 MeV. We investigate self-consistently the radiative synchrotron and inverse Compton signatures of the simulated particle distributions. Important constraints on the diffusive mean free paths of electrons, and the level of electromagnetic field turbulence are identified for three different case study blazars, Mrk 501, BL Lacertae and AO 0235+164. The X-ray excess of AO 0235+164 in a flare state can be modelled as the signature of bulk Compton scattering of external radiation fields, thereby tightly constraining the energy-dependence of the diffusion coefficient for electrons. The concomitant interpretations that turbulence levels decline with remoteness from jet shocks, and the probable significant role for non-gyroresonant diffusion, are posited.
Document ID
20180003261
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Baring, Matthew G.
(Rice Univ. Houston, TX, United States)
Bottcher, Markus
(North-West Univ. Potchefstroom, South Africa)
Summerlin, Errol J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
June 4, 2018
Publication Date
September 15, 2016
Publication Information
Publication: Monthly Notices of the Royal Astronomical Society
Publisher: Oxford University Press
Volume: 464
Issue: 4
ISSN: 0035-8711
e-ISSN: 1365-2966
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN51149
Funding Number(s)
CONTRACT_GRANT: DE-SC0001481
CONTRACT_GRANT: SARCI 64789
CONTRACT_GRANT: NNX10AC79G
Distribution Limits
Public
Copyright
Other

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