Tuesday, November 29, 2011

1111.6551 (Amanda Dotson et al.)

A diagnostic test for determining the location of the GeV emission in powerful blazars    [PDF]

Amanda Dotson, Markos Georganopoulos, Demosthenes Kazanas, Eric Perlman
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 clear 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 few 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.
View original: http://arxiv.org/abs/1111.6551

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