Magnetic Field Geometry in "Red" and "Blue" BL Lacs
Abstract
We compare the systematics of the magnetic field geometry in the "red" low-energy peaked BL Lacs (LBLs) and "blue" high-energy peaked BL Lacs (HBLs) using VLBI polarimetric images. The LBLs are primarily "radio--selected" BL Lacs and the HBLs are primarily "X-ray selected". In contrast to the LBLs, which show predominantly transverse jet magnetic fields, the HBLs show predominantly longitudinal fields. Thus, while the SED peaks of core-dominated quasars, LBLs and HBLs form a sequence of increasing frequency, the magnetic field geometry does not follow an analogous sequence. We briefly investigate possible connections between the observed parsec-scale magnetic field structures and circular polarization measurements in the literature on various spatial scales.
Keywords
Cite
@article{arxiv.astro-ph/0301068,
title = {Magnetic Field Geometry in "Red" and "Blue" BL Lacs},
author = {P. Kharb and D. C. Gabuzda and P. Shastri},
journal= {arXiv preprint arXiv:astro-ph/0301068},
year = {2009}
}
Comments
12 pages, 5 figures, Proceedings of the Amsterdam workshop on "Circular polarisation from relativistic jet sources", to be published in Astrophysics and Space Science, eds. Rob Fender & J-P Macquart