The conspicuous gamma-ray burst of 30 May 1996
2005 (English)In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 28, no 3, 335-338 p.Article in journal (Refereed) Published
The spectra of the majority of bursts exhibit a low-energy power law index, a, that is either a constant or becomes softer with time. However, in the burst of 30 May 1996 a 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 similar to -1.5 to s similar to -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.
Place, publisher, year, edition, pages
2005. Vol. 28, no 3, 335-338 p.
IdentifiersURN: urn:nbn:se:kth:diva-15219ISI: 000233646000022OAI: oai:DiVA.org:kth-15219DiVA: diva2:333260
QC 201005252010-08-052010-08-05Bibliographically approved