Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 10352

GRB 100115A: Swift-XRT refined analysis
2010-01-20T08:55:01Z (14 years ago)
Raffaella Margutti at U. di Milano Bicocca <>
R. Margutti, B. Sbarufatti (INAF-OAB), S. Oates (MSSL/UCL),
report on behalf of the Swift-XRT team:

The Swift ToO observations of the BATSS burst GRB 100115A
(Cummings et al., GCN Circ. 10325) started  40ks  after the
trigger. The XRT data set consists of 8 ks exposure in PC mode
split into two epochs: the first observation was performed
at T0+40 ks, while a second epoch of observations was acquired
at T0+306 ks. The UVOT-enhanced XRT position was given by
Margutti et al. in GCN Circ. 10334.

In the second observation the X-ray source reported by Margutti
et al., GCN Circ.10326 has faded to a level of (1.4 +/- 0.9)e-3
count/sec corresponding to a decay index of -0.7 +/- 0.4.
This source is likely to be the afterglow of GRB 100115A.
No further observations are planned.

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.0 (+1.0, -0.5). The
best-fitting absorption column is consistent with the Galactic value
of 3.1 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum
is 3.4 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1.

The results of the XRT-team automatic analysis are available at

This circular is an official product of the Swift-XRT team.
Looking for U.S. government information and services? Visit