The TeV blazar measurement of the extragalactic background light

Journal Article · Sun Dec 01 04:00:00 EST 2013 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2013/12/022· OSTI ID:22369867

Reesman, Rebecca

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 Fermi and used to measure the EBL spectrum over energies 1 eV–10 eV out to redshift z ∼ 1. Measurements of several TeV blazers are consistent with attenuation, attributed to the EBL at redshift z ∼ 0.1. Here we simultaneously analyze a set of TeV blazers at z ∼ 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 Fermi at lower gamma-ray energies and higher redshifts.

• OSTI ID: 22369867
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 12 Vol. 2013; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATTENUATION
GALAXIES
GAMMA RADIATION
GEV RANGE
PAIR PRODUCTION
RED SHIFT
SPACE
TEV RANGE
UNIVERSE
VISIBLE RADIATION