FLUX AND PHOTON SPECTRAL INDEX DISTRIBUTIONS OF FERMI-LAT BLAZARS AND CONTRIBUTION TO THE EXTRAGALACTIC GAMMA-RAY BACKGROUND

We present a determination of the distributions of the photon spectral index and gamma-ray flux - the so-called log N - log S relation - for the 352 blazars detected with a greater than approximately 7[sigma] detection threshold and located above [+ or -]20[degrees] Galactic latitude by the Large Ar...

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Bibliographic Details
Published in:The Astrophysical journal 2012-07, Vol.753 (1), p.1-11
Main Authors: SINGAL, J, PETROSIAN, V, AJELLO, M
Format: Article
Language:English
Subjects:
Astronomy
ASTROPHYSICS
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
BACKGROUND RADIATION
BL LACERTAE OBJECTS
Blazars
COMPUTERIZED SIMULATION
CORRELATIONS
COSMIC PHOTONS
DATA ANALYSIS
DISTRIBUTION
Earth, ocean, space
EMISSION SPECTRA
Exact sciences and technology
Flux
Fluxes
GALAXIES
GAMMA ASTRONOMY
GAMMA RADIATION
Gamma rays
GAMMA SPECTRA
INDEXES
JETS
Mathematical analysis
Photons
QUASARS
Space telescopes
Spectra
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Summary:We present a determination of the distributions of the photon spectral index and gamma-ray flux - the so-called log N - log S relation - for the 352 blazars detected with a greater than approximately 7[sigma] detection threshold and located above [+ or -]20[degrees] Galactic latitude by the Large Area Telescope of the Fermi Gamma-ray Space Telescope in its first year catalog. We use the non-parametric methods developed by Efron and Petrosian to reconstruct the intrinsic distributions from the observed ones which account for the data truncations introduced by observational bias and includes the effects of the possible correlation between the two variables. We then calculate the contribution of Fermi blazars to the diffuse extragalactic gamma-ray background radiation. Under the assumption that the flux distribution of blazars continues to arbitrarily low fluxes, we calculate the best-fit contribution of all blazars to the total extragalactic gamma-ray output to be 60%, with a large uncertainty.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/753/1/45