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Title: Turbulent, extreme multi-zone model for simulating flux and polarization variability in blazars

The author presents a model for variability of the flux and polarization of blazars in which turbulent plasma flowing at a relativistic speed down a jet crosses a standing conical shock. The shock compresses the plasma and accelerates electrons to energies up to γ{sub max} ≳ 10{sup 4} times their rest-mass energy, with the value of γ{sub max} determined by the direction of the magnetic field relative to the shock front. The turbulence is approximated in a computer code as many cells, each with a uniform magnetic field whose direction is selected randomly. The density of high-energy electrons in the plasma changes randomly with time in a manner consistent with the power spectral density of flux variations derived from observations of blazars. The variations in flux and polarization are therefore caused by continuous noise processes rather than by singular events such as explosive injection of energy at the base of the jet. Sample simulations illustrate the behavior of flux and linear polarization versus time that such a model produces. The variations in γ-ray flux generated by the code are often, but not always, correlated with those at lower frequencies, and many of the flares are sharply peaked. The mean degreemore » of polarization of synchrotron radiation is higher and its timescale of variability shorter toward higher frequencies, while the polarization electric vector sometimes randomly executes apparent rotations. The slope of the spectral energy distribution exhibits sharper breaks than can arise solely from energy losses. All of these results correspond to properties observed in blazars.« less
Authors:
 [1]
  1. Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States)
Publication Date:
OSTI Identifier:
22348302
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; BL LACERTAE OBJECTS; DENSITY; ENERGY LOSSES; ENERGY SPECTRA; GALAXIES; INJECTION; MAGNETIC FIELDS; PLASMA; POLARIZATION; QUASARS; RANDOMNESS; RELATIVISTIC RANGE; REST MASS; ROTATION; SIMULATION; SPECTRAL DENSITY; SYNCHROTRON RADIATION; TURBULENCE