FERMI LARGE AREA TELESCOPE CONSTRAINTS ON THE GAMMA-RAY OPACITY OF THE UNIVERSE
- Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
- W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
- Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy)
- Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France)
- Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
- Rice University, Department of Physics and Astronomy, MS-108, P. O. Box 1892, Houston, TX 77251 (United States)
- Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy)
- Department of Physics, Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)
- Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States)
- Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy)
The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above {approx}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 {approx} 3, and GRBs with redshift up to z {approx} 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.
- OSTI ID:
- 21471275
- Journal Information:
- Astrophysical Journal, Vol. 723, Issue 2; Other Information: DOI: 10.1088/0004-637X/723/2/1082; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
COSMIC GAMMA BURSTS
ENERGY DEPENDENCE
GAMMA RADIATION
GEV RANGE 10-100
PHOTONS
RED SHIFT
TELESCOPES
ULTRAVIOLET RADIATION
UNIVERSE
WAVELENGTHS
BOSONS
COSMIC RADIATION
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
GEV RANGE
IONIZING RADIATIONS
MASSLESS PARTICLES
PRIMARY COSMIC RADIATION
RADIATIONS