Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-01-09
Astrophys.J.643:266-275,2006
Astronomy and Astrophysics
Astrophysics
26 pages, 8 figures, 4 tables. Now accepted for publication in The Astrophysical Journal
Scientific paper
10.1086/502796
The recent association of several short gamma-ray bursts (GRBs) with early type galaxies with low star formation rate demonstrates that short bursts arise from a different progenitor mechanism than long bursts. However, since the duration distributions of the two classes overlap, membership is not always easily established. The picture is complicated by the occasional presence of softer, extended emission lasting tens of seconds after the initial spike-like emission. We show that the fundamental defining characteristic of the short burst class is that the initial spike exhibits negligible spectral evolution at energies above ~ 25 keV. This behavior is nearly ubiquitous for the 260 bursts with T90 < 2 s, where the BATSE TTE data completely included the initial spike. The same signature obtains for one HETE-2 and six Swift/BAT short bursts. Analysis of a small sample of "short" BATSE bursts with the most intense extended emission shows that the same lack of evolution on the pulse timescale obtains for the extended emission. The dynamic range in the ratio of peak intensities, spike : extended, is ~ 10^4. For some bursts, the extended emission is only a factor of 2-5 less intense. A high Lorentz factor, ~ 500-1000, might explain the negligible lags observed in short bursts.
Bonnell Jerry T.
Norris Jay P.
No associations
LandOfFree
Short Gamma-Ray Bursts with Extended Emission does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Short Gamma-Ray Bursts with Extended Emission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Short Gamma-Ray Bursts with Extended Emission will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-683643