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This content will become publicly available on November 17, 2018

Title: Probing the EBL Evolution at High Redshift Using GRBs Detected with the Fermi-LAT

The extragalactic background light (EBL), from ultraviolet to infrared wavelengths, is predominantly due to emission from stars, accreting black holes and reprocessed light due to Galactic dust. The EBL can be studied through the imprint it leaves, via γ–γ absorption of high-energy photons, in the spectra of distant γ-ray sources. The EBL has been probed through the search for the attenuation it produces in the spectra of BL Lacertae (BL Lac) objects and individual γ-ray bursts (GRBs). GRBs have significant advantages over blazars for the study of the EBL especially at high redshifts. Here we analyze a combined sample of 22 GRBs, detected by the Fermi Large Area Telescope between 65 MeV and 500 GeV. We report a marginal detection (at the ~2.8σ level) of the EBL attenuation in the stacked spectra of the source sample. This measurement represents a first constraint of the EBL at an effective redshift of ~1.8. Here, we combine our results with prior EBL constraints and conclude that Fermi-LAT is instrumental to constrain the UV component of the EBL. We discuss the implications on existing empirical models of EBL evolution.
 [1] ; ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [1] ; ORCiD logo [3] ; ORCiD logo [1] ; ORCiD logo [4] ;  [5] ; ORCiD logo [6]
  1. Clemson Univ., Clemson, SC (United States)
  2. Stanford Univ., Stanford, CA (United States). SLAC National Accelerator Lab.
  3. Univ. Complutense de Madrid, Madrid (Spain)
  4. Max-Planck-Institut fur Astrophysik, Garching (Germany)
  5. Naval Research Lab., Washington, D.C. (United States)
  6. Stockholm Univ., Stockholm (Sweden)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 850; Journal Issue: 1; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; cosmology: observations; galaxies: high-redshift; gamma-ray burst: general; gamma-rays: observations; gamma-rays: theory
OSTI Identifier: