The TeV Blazar Measurement of the Extragalactic Background Light

Abstract

Gamma-rays propagating through space are likely to be extinguished via electron-positron pair production off of the ambient extragalactic background light (EBL). The spectrum of the EBL is produced by starlight (and starlight reprocessed by dust) from all galaxies throughout the history of the Universe. The attenuation of 40 - 400 GeV gamma-rays has been observed by \textit{Fermi} and used to measure the EBL spectrum over energies 1 eV -10 eV out to redshift $z\sim 1$. Measurements of several TeV blazers are consistent with attenuation, attributed to the EBL at redshift $z\sim 0.1$. Here we simultaneously analyze a set of TeV blazers at $z\sim 0.1$ to measure the optical depth for 100 GeV - 10 TeV gamma-rays, which interact with EBL of energies 0.05 eV - 5 eV. Using a suite of models for the EBL, we show that the optical depth indicated by TeV blazar attenuation is in good agreement with the optical depths measured by \textit{Fermi} at lower gamma-ray energies and higher redshifts.

10 pages, 3 figures Accepted by JCAP

References in corpus (11)

• The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
• New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200
• New limits on the density of the extragalactic background light in the optical to the far-infrared from the spectra of all known TeV blazars
• Discovery of very high energy gamma-ray emission from the low-frequency peaked BL Lacertae object BL Lacertae
• Detection of the cosmic γ-ray horizon from multiwavelength observations of blazars
• The Resolved NIR Extragalactic Background
• The Resolved Near-Infrared Extragalactic Background
• Discovery of VHE gamma-rays from the high-frequency-peaked BL Lac object RGB J0152+017
• DIRBE Minus 2MASS: Confirming the CIRB in 40 New Regions at 2.2 and 3.5 Microns
• Gamma-rays from Blazars and the Extragalactic Background Light
• Extragalactic background light inferred from AEGIS galaxy SED-type fractions

Cited by in corpus (2)

• Estimation of the Extragalactic Background Light using TeV Observations of BL~Lacs
• Probing the Scale of ALP Interactions with Fermi Blazars