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Title: Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived from First-Year Fermi Large Area Telescope Data

Journal Article · · Physical Review Letters
 [1]
  1. Naval Research Lab. (NRL), Washington, DC (United States); National Academy of Sciences, Washington, DC (United States); et al.
+ Show Author Affiliations

Here, we report on the first Fermi Large Area Telescope (LAT) measurements of the so-called “extragalactic” diffuse γ -ray emission (EGB). This component of the diffuse γ -ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modeling of the bright foreground diffuse Galactic γ -ray emission, the detected LAT sources, and the solar γ -ray emission. We also find the spectrum of the EGB is consistent with a power law with a differential spectral index γ = 2.41 ± 0.05 and intensity I ( > 100 MeV ) = ( 1.03 ± 0.17 ) × 10 - 5 cm -2 s - 1 sr - 1 , where the error is systematics dominated. The EGB spectrum, presented here, is featureless, less intense, and softer than that derived from EGRET data.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE
Contributing Organization:
Fermi LAT Collaboration
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1357577
Journal Information:
Physical Review Letters, Vol. 104, Issue 10; ISSN 0031-9007
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 426 works
Citation information provided by
Web of Science

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The denoised, deconvolved, and decomposed Fermi γ -ray sky : An application of the D journal September 2015
THE LUMINOSITY FUNCTION OF FERMI -DETECTED FLAT-SPECTRUM RADIO QUASARS journal May 2012
GeV OBSERVATIONS OF STAR-FORMING GALAXIES WITH THE FERMI LARGE AREA TELESCOPE journal August 2012
Extragalactic Background Light from Hierarchical Galaxy Formation: Gamma-Ray Attenuation up to the Epoch of Cosmic Reionization and the First Stars journal April 2013
IMPLICATIONS OF PLASMA BEAM INSTABILITIES FOR THE STATISTICS OF THE FERMI HARD GAMMA-RAY BLAZARS AND THE ORIGIN OF THE EXTRAGALACTIC GAMMA-RAY BACKGROUND journal July 2014
THE FERMI LARGE AREA TELESCOPE ON ORBIT: EVENT CLASSIFICATION, INSTRUMENT RESPONSE FUNCTIONS, AND CALIBRATION journal October 2012
TOMOGRAPHY OF THE FERMI -LAT γ -RAY DIFFUSE EXTRAGALACTIC SIGNAL VIA CROSS CORRELATIONS WITH GALAXY CATALOGS journal March 2015
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Decaying Dark Matter in Supersymmetric Model and Cosmic-Ray Observations text January 2010
Constraints on cosmic-ray propagation models from a global Bayesian analysis text January 2010
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Dark matter subhaloes as gamma-ray sources and candidates in the first Fermi-LAT catalogue text January 2011
Cosmic Super-Strings and Kaluza-Klein Modes text January 2012
Fermi-LAT Observations of the Diffuse Gamma-Ray Emission: Implications for Cosmic Rays and the Interstellar Medium text January 2012
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Unidentified sources in the Fermi-LAT second source catalog: the case for DM subhalos text January 2012
Extragalactic Background Light from Hierarchical Galaxy Formation: Gamma-ray Attenuation up to the Epoch of Cosmic Reionization and the First Stars text January 2012
Discrete Gauge Symmetry and Aharonov-Bohm Radiation in String Theory text January 2013
Imprint of Multi-component Dark Matter on AMS-02 text January 2013
Constraints on diffuse gamma-ray emission from structure formation processes in the Coma cluster text January 2013
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