Blazar Compton efficiencies: Fermi, external photons and the Sequence

J. A. Gupta; I. W. A. Browne; M. W. Peel

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arXiv · 1106.5172

Blazar Compton efficiencies: Fermi, external photons and the Sequence

J. A. Gupta·I. W. A. Browne·M. W. Peel

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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.

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J. A. Gupta, I. W. A. Browne, M. W. Peel. 2011-06-25. Blazar Compton efficiencies: Fermi, external photons and the Sequence. https://arxiv.org/abs/1106.5172

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