The Origin of Complex Behavior of Linearly Polarized Components in Parsec-Scale Jets
Abstract
Evidence that the magnetic fields of extragalactic jets have a significant fraction of their energy in a random component is briefly summarized, and a detailed model of evolving, jet polarization structures is constructed, based on this picture. The evolving magnetic field structure of an oblique shock complex that forms in a relativistic jet simulation is explored by using velocity data from the hydrodynamical simulation to advect an initially random magnetic field distribution. Radiative transfer calculations reveal that emission from a propagating region of magnetic field, `ordered' by the shock, and lying approximately transverse to the flow direction, merges with that from an evolving sheared region at the flow periphery. If such a flow were barely resolved, observation would suggest evolution from a somewhat oblique, to a more longitudinal, magnetic field structure with respect to the flow axis, while higher resolution observations would infer a component following a non-linear trajectory, and with a magnetic field orientation that rotates during evolution. This result highlights the ambiguity in interpreting VLBP data, and illustrates the importance of simulations in providing a framework for proper interpretation of such data.
Cite
@article{arxiv.astro-ph/0411725,
title = {The Origin of Complex Behavior of Linearly Polarized Components in Parsec-Scale Jets},
author = {Philip A. Hughes},
journal= {arXiv preprint arXiv:astro-ph/0411725},
year = {2009}
}
Comments
Accepted for publication in ApJ (Part I). Low res. figures; originals may be obtained from the "Relativistic Flows" section of http://www.astro.lsa.umich.edu/users/hughes/