The extragalactic background light from the measurements of the attenuation of high-energy gamma-ray spectrum

Abstract

The attenuation of high-energy gamma-ray spectrum due to the electron-positron pair production against the extragalactic background light (EBL) provides an indirect method to measure the EBL of the universe. We use the measurements of the absorption features of the gamma-rays from blazars as seen by Fermi Gamma-ray Space Telescope to explore the EBL flux density and constrain the EBL spectrum, star formation rate density (SFRD) and photon escape fraction from galaxies out to z=6. Our results are basically consistent with the existing determinations of the quantities. We find a larger photon escape fraction at high redshifts, especially at z=3, compared to the result from the recent Ly-alpha measurements. Our SFRD result is consistent with the data from both gamma-ray burst and UV observations in 1-sigma level. However, the average SFRD we obtain at z>~3 matches the gamma-ray data better than the UV data. Thus our SFRD result at z>~6 favors that it is sufficiently high enough to reionize the universe.

5 pages, 3 figures, ApJL accepted

References in corpus (4)

• The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
• Extragalactic Background Light from Hierarchical Galaxy Formation: Gamma-ray Attenuation up to the Epoch of Cosmic Reionization and the First Stars
• The energy output of the Universe from 0.1 micron to 1000 micron
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Cited by in corpus (6)

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• Modeling the Extragalactic Background Light and the Cosmic Star Formation History
• Axion decay and anisotropy of near-IR extragalactic background light
• Gamma-rays as probes of the Universe
• Testing CIBER cosmic infrared background measurements and axionlike particles with observations of TeV blazars
• Probing $\mu$eV ALPs with future LHAASO observation of AGN $\gamma$-ray spectra