The hardness evolution of gamma-ray burst pulses
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
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