Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2009-06-12
Res.Astron.Astrophys.9:1103-1118,2009
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
19 pages, minor editorial changes, references updated, published in Research in Astronomy and Astrophysics (http://www.raa-j
Scientific paper
10.1088/1674-4527/9/10/003
We compare the properties of optically dark GRBs, defined by the optical-to-X-ray spectral index beta_OX<0.5, and normal ones discovered by the Swift satellite before the year 2008 in a statistical way, using data collected from the literature and online databases. Our sample include 200 long bursts, 19 short bursts, and 10 with measured high redshifts (z>=4). The ratio of dark bursts is found to be about 10-20%, and is similar between long bursts, short ones, and the high-z sub-sample. The result for long bursts is consistent with both the pre-Swift sample and studies by other authors on smaller Swift samples. The existence of dark short GRBs is pointed out for the first time. The X-ray derived hydrogen column densities of dark GRBs clearly prefer large values compared with those of normal bursts. This supports the dust extinction scenario as the main cause of dark GRBs. Other possibilities like very high redshifts and non-standard emission mechanisms are less likely although not fully excluded.
Deng Jian
Wang Jeffrey
Zheng Wei
No associations
LandOfFree
Statistical studies of optically dark gamma-ray bursts in the Swift era 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 Statistical studies of optically dark gamma-ray bursts in the Swift era, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Statistical studies of optically dark gamma-ray bursts in the Swift era will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-134801