Intergalactic Extinction of High Energy Gamma-Rays

Abstract

We discuss the determination of the intergalactic pair-production absorption coefficient (Stecker & De Jager 1998) making use of an empirically based calculation of the IR background spectrum (Malkan & Stecker 1998) which agrees well with recent data and constraints on the IR background. While the Whipple observations of Mrk421 hint at extragalactic absorption, the new HEGRA observations of Mrk501 appear to strongly indicate such absorption. We discuss the determination of absorption at higher redshifts (Salamon & Stecker 1998). We also give a predicted spectrum, with absorption included, for PKS2155-304, which, at a redshift of 0.12, is the highest redshift TeV source yet observed.

15 latex pages with 7 figures, to be published in the Proc. Harvard workshop on TeV Astrophysics of Extragalactic Sources

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Cited by in corpus (14)

• Intergalactic Photon Spectra from the Far IR to the UV Lyman Limit for $0<z<6$ and the Optical Depth of the Universe to High Energy Gamma-Rays
• A new determination of the extragalactic diffuse gamma-ray background from EGRET data
• Multi-Epoch Multiwavelength Spectra and Models for Blazar 3C~279
• Very High Energy Gamma-Ray Astronomy
• Probing Galaxy Formation with TeV Gamma Ray Absorption
• Reanalysis of the high energy cutoff of the 1997 Mkn 501 TeV energy spectrum
• New constraints on the cosmic mid-infrared background using TeV gamma-ray astronomy
• Constraints on the Very High Energy Emission from BL Lacertae Objects
• Cosmic Physics: The High Energy Frontier
• Upper Limits on the Extragalactic Background Light from the Gamma-Ray Spectra of Blazars
• A Very High Energy Gamma-Ray Spectrum of 1ES 2344+514
• Neutrino production in UHECR proton interactions in the infrared background
• Diffuse Gamma Rays: Galactic and Extragalactic Diffuse Emission
• High Energy Particles from the Universe