Location of the Gamma-Ray Flaring Emission in the Parse-Scale Jet of the BL Lac Object AO 0235+164

International Journal of Modern Physics Conference Series 12/2011; DOI: 10.1142/S2010194512004709
Source: arXiv


We locate the gamma-ray and lower frequency emission in flares of the BL Lac
object AO 0235+164 at >12pc in the jet of the source from the central engine.
We employ time-dependent multi-spectral-range flux and linear polarization
monitoring observations, as well as ultra-high resolution (~0.15
milliarcsecond) imaging of the jet structure at lambda=7mm. The time
coincidence in the end of 2008 of the propagation of the brightest superluminal
feature detected in AO 0235+164 (Qs) with an extreme multi-spectral-range
(gamma-ray to radio) outburst, and an extremely high optical and 7mm (for Qs)
polarization degree provides strong evidence supporting that all these events
are related. This is confirmed at high significance by probability arguments
and Monte-Carlo simulations. These simulations show the unambiguous correlation
of the gamma-ray flaring state in the end of 2008 with those in the optical,
millimeter, and radio regime, as well as the connection of a prominent X-ray
flare in October 2008, and of a series of optical linear polarization peaks,
with the set of events in the end of 2008. The observations are interpreted as
the propagation of an extended moving perturbation through a re-collimation
structure at the end of the jet's acceleration and collimation zone.

Download full-text


Available from: Jose L. Gómez, Jan 10, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We have investigated via two-dimensional relativistic MHD simulations the long-term evolution of turbulence created by a relativistic shock propagating through an inhomogeneous medium. In the postshock region, magnetic field is strongly amplified by turbulent motions triggered by preshock density inhomogeneities. Using a long-simulation box we have followed the magnetic-field amplification until it is fully developed and saturated. The turbulent velocity is sub-relativistic even for a strong shock. Magnetic-field amplification is controled by the turbulent motion and saturation occurs when the magnetic energy is comparable to the turbulent kinetic energy. Magnetic-field amplification and saturation depend on the initial strength and direction of the magnetic field in the preshock medium, and on the shock strength. If the initial magnetic field is perpendicular to the shock normal, the magnetic field is first compressed at the shock and then can be amplified by turbulent motion in the postshock region. Saturation occurs when the magnetic energy becomes comparable to the turbulent kinetic energy in the postshock region. If the initial magnetic field in the preshock medium is strong, the postshock region becomes turbulent but significant field amplification does not occur. If the magnetic energy after shock compression is larger than the turbulent kinetic energy in the postshock region, significant field amplification does not occur. We discuss possible applications of our results to gamma-ray bursts and active galactic nuclei.
    Monthly Notices of the Royal Astronomical Society 01/2014; 439(4). DOI:10.1093/mnras/stu196 · 5.11 Impact Factor

We use cookies to give you the best possible experience on ResearchGate. Read our cookies policy to learn more.