Blazar Compton efficiencies: Fermi, external photons and the Sequence
Abstract
The Fermi-LAT survey provides a large sample of blazars selected on the strength of their inverse Compton emission. We cross-correlate the first Fermi-LAT catalogue with the CRATES radio catalogue and use this sample to investigate whether blazar gamma-ray luminosities are influenced by the availability of external photons to be up-scattered. Using the 8.4 GHz flux densities of their compact radio cores as a proxy for their jet power, we calculate their Compton Efficiency parameters, which measure the ability of jets to convert power in the form of ultra-relativistic electrons into Compton gamma-rays. We find no clear differences in Compton efficiencies between BL Lac objects and FSRQs and no anti-correlation between Compton efficiency and synchrotron peak frequency. This suggests that the scattering of external photons is energetically unimportant compared to the synchrotron self-Compton process. These results contradict the predictions of the blazar sequence.
Cite
@article{arxiv.1106.5172,
title = {Blazar Compton efficiencies: Fermi, external photons and the Sequence},
author = {J. A. Gupta and I. W. A. Browne and M. W. Peel},
journal= {arXiv preprint arXiv:1106.5172},
year = {2011}
}
Comments
6 pages, 5 figures. Submitted to MNRAS