Abstract

The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above similar to 10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and gamma-ray bursts (GRBs). The Large Area Telescope on board Fermi detects a sample of gamma-ray blazars with redshift up to z similar to 3, and GRBs with redshift up to z similar to 4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the universe at various energies and redshifts and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. can be ruled out with high confidence.

Autore Pugliese

• Loparco Francesco , Giordano Francesco , Spinelli Paolo , Fusco Piergiorgio , Raino' Silvia

Tutti gli autori

• LOPARCO F.;GIORDANO F.;SPINELLI P.;FUSCO P.;RAINO' S.

Titolo volume/Rivista

Non Disponibile

Anno di pubblicazione

2010

ISSN

0004-637X

ISBN

Non Disponibile

Numero di citazioni Wos

93

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

111

Ultimo Aggiornamento Citazioni

Non Disponibile

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile