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Lecture 4: Light extinction: Compton scattering Gamma-Ray Bursts
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GRBs are brief flashes of soft -ray radiation (100 keV), discovered in the 1970’s, the origin of which was not known until 1997 CGRO-BATSE
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Compton thick sources In Seyfert 2 galaxies there is evidence of cold material around the nucleus and of absorption caused by this material in excess of the Galactic one. The local column density of this material is optically thick to Compton scattering Bassani et al. 1999, ApJS, 121, 473 Matt et al. 1999, New Astronomy, 4, 191
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Compton-thick sources
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CGRO spectrum of a GRB
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relativistic conditions are implied: Lorentz factor
CGRO-BATSE (Fishman & Meegan 1995) Light curves of GRBs Fluence ~ if cosmological relativistic conditions are implied: Lorentz factor
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The GRB distribution is isotropic
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