2005/12/31 by Alessandro Drago, Giuseppe Pagliara
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Gamma-ray bursts and supernovae #astro-ph #hep-ph #nucl-th
paper · pdf · doi:10.1086/519728
published as Astrophys.J.665:1227-1234,2007 · 17 pages, 7 figures. New version after referee's comments. Two figures added
arxiv created 2006/10/04 · openalex publication_date 2007/08/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We perform a statistical analysis of the temporal structure of long gamma-ray bursts (GRBs). We consider a sample of bursts in which a long quiescent time is present. By comparing the prequiescent with the postquiescent emission we show that they display similar temporal structures, hardness ratios, and emitted powers, but, on average, the postquiescent emission is roughly twice as long as the prequiescent emission. We then analyze a sample of long and bright GRBs (long and faint GRBs are not included) and find that the average duration of the quiescent times is comparable to the average duration of the emission periods. This leads us to suggest an interpretation of quiescent times as due to dormancy periods of the inner engine. The interpretation of quiescent times as instead caused by stochastic modulations of a continuous wind is less plausible due to the larger energy requirements that it imposes on the inner engine. Interestingly, before and after a dormancy period the inner engine produces similar emissions.