SPECTRAL ANALYSIS OF <i>FERMI</i> -LAT BLAZARS ABOVE 50 GEV [electronic resource].

Published:: Washington, D.C. : United States. Dept. of Energy, 2015.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description:: Article numbers L34 : digital, PDF file
Additional Creators:: SLAC National Accelerator Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

We present an analysis of the intrinsic (unattenuated by the extragalactic background light, EBL) power-law spectral indices of 128 extragalactic sources detected up to z ~ 2 with the Fermi-Large Area Telescope (LAT) at very high energies (VHEs, E ≥50 GeV). The median of the intrinsic index distribution is 2.20 (versus 2.54 for the observed distribution). We also analyze the observed spectral breaks (i.e., the difference between the VHE and high energy, HE, 100 MeV ≤ E ≤ 300 GeV, spectral indices). The Fermi-LAT has now provided a large sample of sources detected both at VHE and HE with comparable exposure that allows us to test models of extragalactic γ-ray photon propagation. We find that our data are compatible with simulations that include intrinsic blazar curvature and EBL attenuation. There is also no evidence of evolution with redshift of the physics that drives the photon emission in high-frequency synchrotron peak (HSP) blazars. This makes HSP blazars excellent probes of the EBL.

Report Numbers:

E 1.99:1354852

Subject(s):

Astronomy And Astrophysics

Note:

Published through SciTech Connect.
11/04/2015.
The Astrophysical Journal. Letters 813 2 ISSN 2041-8213 AM
Alberto Domínguez; Marco Ajello.

Funding Information:

AC02-76SF00515

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