in Proc. of the 1st GLAST Symposium, Feb 5-8, 2007,
Stanford, AIP, Eds. S. Ritz, P. F. Michelson, and C. Meegan
For a PDF version of the article, click
For a PDF version of the article, click here.
Abstract. One way to understand the nonthermal history of the universe is by establishing the origins of the unresolved and truly diffuse extragalactic rays. Dim blazars and radio / galaxies certainly make an important contribution to the galactic -ray background given the EGRET discoveries, and previous treatments are reviewed and compared with a new analysis. Studies of the -ray intensity from cosmic rays in star-forming galaxies and from structure formation shocks, as well as from dim GRBs, are briefly reviewed. A new hard -ray source class seems required from the predicted aggregate intensity compared with the measured intensity.
Keywords: gamma-rays - blazars - background radiations
PACS: 95.85.Pw, 98.54.Cm, 98.62.Nx, 98.70.Rz, 98.70.Vc
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