Determining the location of the GeV emission in powerful blazars
Abstract
An issue currently under debate in the literature is how far from the black hole is the Fermi-observed GeV emission of powerful blazars emitted. Here we present a diagnostic tool for testing whether the GeV emission site is located within the sub-pc broad emission line (BLR) region or further out in the pc scale molecular torus (MT) environment. Within the BLR the scattering takes place at the onset of the Klein-Nishina regime, causing the electron cooling time to become almost energy independent and as a result, the variation of high-energy emission is expected to be achromatic. Contrarily, if the emission site is located outside the BLR, the expected GeV variability is energy-dependent and with amplitude increasing with energy. We demonstrate this using time-dependent numerical simulations of blazar variability and discuss the applicability of our method.
Keywords
Cite
@article{arxiv.1206.0012,
title = {Determining the location of the GeV emission in powerful blazars},
author = {Amanda Dotson and Markos Georganopoulos and Demosthenes Kazanas and Eric Perlman},
journal= {arXiv preprint arXiv:1206.0012},
year = {2012}
}
Comments
2012 Fermi & Jansky Proceedings - eConf C1111101