| Issue |
Astron. Astrophys. Suppl. Ser.
Volume 138, Number 3, September 1999
Gamma-Ray Bursts in the Afterglow Era Contents Rome, November 3-6, 1998
|
|
|---|---|---|
| Page(s) | 401 - 402 | |
| DOI | https://doi.org/10.1051/aas:1999280 | |
| Published online | 15 September 1999 | |
The hardness evolution of gamma-ray burst pulses
1
Department of Space Physics and Astronomy, 6100 S. Main, Rice University, Houston, TX 77005-1892, U.S.A.
2
Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899, U.S.A.
3
Center for Astrophysics and Space Sciences 0424, University of California at San Diego, La Jolla, CA 92093, U.S.A.
Send offprint request to: A. Crider
Received:
21
January
1999
Accepted:
21
April
1999
We have analyzed the evolution of the spectral hardness parameter,
Epk (the maximum of the
spectrum) as a function of fluence in gamma-ray bursts.
We fit 41 pulses within 26 bursts with the
trend reported by Liang & Kargatis (1996) which found that Epk decays exponentially with
respect to photon fluence 
. We also fit these pulses
with a slight modification of this trend, where Epk decays
linearly with energy fluence. In both cases, we found the
set of 41 pulses
to be consistent with the trend.
Key words: gamma-ray: bursts, observations
© European Southern Observatory (ESO), 1999