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T.M. Freismuth, T. Giblin, J. Hakkila (The College of Charleston, SC)
We examine the spectral properties of quiescent Gamma-Ray Bursts (GRB) in the BATSE catalog. Quiescent GRBs are bursts whose emission drops below the background level for some period of time that is comparable to the duration of the emission episode, followed by a resurgence of emission. A careful inspection of late times in GRB light curves, after the GRB has presumably ended, reveals some instances of additional emission. This "post-quiscent" emission may have one of two possible origins in the internal/external shock model: (1) it is the result of the internal shocks froms the delayed activity in the progenitor, or (2) it is the onset of the afterglow. The spectral evolution of a GRB can be traced in a graphical form using a color-color diagram (CCD) method, as described by Giblin et al. 2002, where the spectral evolution trend in the CCD is characterized by a power law function. Early results show a decrease in the power law index from the pre- to post- quiescent emission, possibly suggesting a different mechanism at work.
We gratefully acknowledge NASA support under grant NRA-98-OSS-03 (the Applied Information Systems Research Program), NSF support under grant AST00-98499 (Research in Undergraduate Institutions), and NASA grant NAG 5-11017.
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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.