Limits on the Isotropic Diffuse Flux of Ultrahigh Energy {gamma} Radiation

Journal Article · Mon Sep 01 00:00:00 EDT 1997 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.79.1805· OSTI ID:560706

Chantell, M C; Covault, C E; Cronin, J W; Fick, B E; Fortson, L F; Fowler, J W; Green, K D; Newport, B J; Ong, R A; Oser, S ^[1]; Catanese, M A; Glasmacher, M A; Matthews, J; Nitz, D F; Sinclair, D; van der Velde, J C ^[2]; Kieda, D B ^[3]

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1. The Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)
2. Department of Physics, The University of Michigan, Ann Arbor, Michigan 48109 (United States)
3. Department of Physics, The University of Utah, Salt Lake City, Utah 84112 (United States)

Diffuse ultrahigh energy {gamma} radiation can arise from a variety of astrophysical sources, including the interaction of 10{sup 20} eV cosmic rays with the 2.7K microwave background radiation or the collapse of topological defects created in the early Universe. We describe a sensitive search for diffuse {gamma} rays at ultrahigh energies using the Chicago Air Shower Array{endash}Michigan Muon Array experiment. An isotropic flux of radiation is not detected, and we place stringent upper limits on the fraction of the {gamma}-ray component relative to cosmic rays ({lt}10{sup {minus}4}) at energies from 5.7{times}10{sup 14} to 5.5{times}10{sup 16} eV. This result represents the first comprehensive constraint on the {gamma}-ray flux at these energies. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 560706
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 10 Vol. 79; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ASTROPHYSICS
BACKGROUND RADIATION
COSMIC MUONS
COSMIC RAY FLUX
DEFECTS
DIFFUSION
EXTENSIVE AIR SHOWERS
GAMMA RADIATION
MICROWAVE RADIATION
RADIATION FLUX
TOPOLOGY