AAS Meeting #193 - Austin, Texas, January 1999
Session 79. Gamma-Ray Bursts I
Oral, Friday, January 8, 1999, 10:00-11:30am, Ballroom A

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[79.06] Probing the Spectral Evolution of BATSE Gamma-Ray Bursts using Color-Color Diagrams

T. Giblin (U. Alabama in Hunstville /MSFC), C. Kouveliotou (USRA / MSFC), J. van Paradijs (U. Alabama in Hunstville / U. Amsterdam), G. J. Fishman (NASA / MSFC)

We have performed a study of gamma-ray burst (GRB) spectral evolution through the use of model independent time resolved color-color diagrams (CCDs). The CCD can be interpreted as a spectral fingerprint of the burst in the 25 - 2000 keV energy range. An analysis of long bright GRBs reveals several distinct trends in the two-color plane. The global hard-to-soft evolution commonly reported in previous studies (e.g. Ford et al. 1995) is recovered in addition to several new properties that are not easily explained in the context of spectral modeling. A comparison of GRB CCDs and CCDs produced from simulations of energy dependent single pulse time histories suggest a GRB spectral self-similarity and lend support to the GRB pulse paradigm.

The author(s) of this abstract have provided an email address for comments about the abstract: tim.giblin@msfc.nasa.gov

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