Gamma - Gamma-Ray Bursts Many of the same considerations...

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Gamma-Ray Bursts Many of the same considerations applicable to relativistic jets in AGN also seem to apply to gamma-ray bursts and their afterglows. The energy requirements become much more tractable if the luminosity is enhanced by beaming, and some of the afterglow light curves suggest that indeed the beaming is within a fairly narrow solid angle (instead of the isotropic but beamed emission we'd see from a relativistic fireball). To briefly review properties of gamma-ray bursts: Bursts are detected at random times from random directions; in both cases "random" means satisfying Poisson statistics to high accuracy. The distribution on the sky is uniform to a very high level (see this equal-area projection of the 2704 BATSE bursts). the log N - log S relation is highly non uniform, with too few faint bursts (in contrast to the situation with, for example, quasars). Typical bursts have a power-law like spectrum. A good set of overview reviews is included in the December 1995 PASP. Cosmic gamma-ray bursts were discovered serendipitously in 1965, while searching for terrestrial bursts which would indicate violations of the nuclear test-ban treaty. This happened when the Vela satellites were orbited; one might suspect that there was a comparable Soviet program, but no public information seems to have been forthcoming. The first report in public was in 1973; the brief abstract continued to describe the state of our knowledge for 20 years: Bursts of high-energy
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This note was uploaded on 11/10/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.

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Gamma - Gamma-Ray Bursts Many of the same considerations...

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