IDENTIFYING BREAKS AND CURVATURE IN THE FERMI SPECTRA OF BRIGHT FLAT SPECTRUM RADIO QUASARS

IDENTIFYING BREAKS AND CURVATURE IN THE FERMI SPECTRA OF BRIGHT FLAT SPECTRUM RADIO QUASARS

Knowing the site of [gamma]-ray emission in active galactic nucleus jets will do much for our understanding of the physics of the source. In particular, if the emission region is close to the black hole then absorption of [gamma]-rays with photons from the broad-line region could become significant....

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Bibliographic Details
Published in:The Astrophysical journal 2012-12, Vol.761 (1), p.1-8
Main Authors: HARRIS, J, DANIEL, M. K, CHADWICK, P. M
Format: Article
Language:eng
Subjects:
ABSORPTION SPECTROSCOPY
Astronomy
ASTROPHYSICS
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
BL LACERTAE OBJECTS
BLACK HOLES
Breaking
Earth, ocean, space
Emission
EMISSION SPECTROSCOPY
Exact sciences and technology
Flats
GALAXIES
GALAXY NUCLEI
GAMMA ASTRONOMY
GAMMA RADIATION
GAMMA SPECTRA
JETS
Mathematical analysis
Mathematical models
PHOTON EMISSION
QUASARS
Radio
Spectra
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Summary:Knowing the site of [gamma]-ray emission in active galactic nucleus jets will do much for our understanding of the physics of the source. In particular, if the emission region is close to the black hole then absorption of [gamma]-rays with photons from the broad-line region could become significant. Such absorption is predicted to produce two specific spectral breaks in the [gamma]-ray spectra of Flat Spectrum Radio Quasars (FSRQs). We test this hypothesis using three years of Fermi observations of nine bright FSRQs. A simple power-law fit to the spectrum of each source can be significantly improved by introducing a break, but the break energies are inconsistent with those predicted by the double-absorber model. In some cases the fit can be further improved by a log-parabola. In addition, by dividing the data from each source into two equal epochs we find that the best description of an object's spectrum often varies between a log-parabola and a broken power law.
ISSN:0004-637X
1538-4357