The conspicuous gamma-ray burst of 30 May 1996
Abstract
The spectra of the majority of bursts exhibit a low-energy power law index, alpha, that is either a constant or becomes softer with time. However, in the burst of 30 May 1996 alpha becomes harder. Here we show that this behavior can be explained by a hybrid model consisting of a thermal and a non-thermal component. In this burst the power-law index of the non-thermal component changes drastically from s ~ -1.5 to s ~ -0.67 at approximately 5 seconds after the trigger, thereby revealing, at low energies, the thermal component with its hard Rayleigh-Jeans tail. This leads to the large alpha-values that are found if the Band function is fitted to the spectra. We suggest that the change in s could be due to a transition from fast to slow cooling of the electrons emitting in the BATSE range. This could be due to the fact that the magnetic field strength becomes weaker.
Keywords
Cite
@article{arxiv.astro-ph/0504542,
title = {The conspicuous gamma-ray burst of 30 May 1996},
author = {Felix Ryde and Milan Battelino},
journal= {arXiv preprint arXiv:astro-ph/0504542},
year = {2010}
}
Comments
Submitted to Il Nuovo Cimento (4th Workshop Gamma-Ray Bursts in the Afterglow Era, Rome, 18-22 October 2004)