[vsnet-grb-info 7084] Possible GRB 081211B - Swift-XRT analysis
GCN Circulars
gcncirc at capella.gsfc.nasa.gov
Sat Dec 13 18:19:54 JST 2008
TITLE: GCN CIRCULAR
NUMBER: 8666
SUBJECT: Possible GRB 081211B - Swift-XRT analysis
DATE: 08/12/13 09:19:47 GMT
FROM: Kim Page at U.of Leicester <kpa at star.le.ac.uk>
K.L. Page, P.A. Evans (U. Leicester) and S.T. Holland (CRESST/USRA/GSFC)
report on behalf of the Swift-XRT team:
Swift-XRT performed a Target of Opportunity observation of the possible
BAT Slew Survey (BATSS) burst GRB 081211B (Copete et al., GCN Circ. 8661),
starting 81.6 ks after the slew in which it was detected, and found a
single, uncatalogued X-ray source within the BATSS error circle.
Using 1878 s of XRT Photon Counting mode data and 4 UVOT images, we find
an astrometrically corrected X-ray position (using the XRT-UVOT alignment
and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =
168.2646, 53.8300 which is equivalent to:
RA (J2000): 11 13 3.49
Dec (J2000): +53 49 48.1
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
During the initial observation (81.6-92 ks), the mean X-ray count rate was
0.035 +/- 0.005 count s^-1. A second observation (126-133 ks) showed a
count rate of 0.018 +/- 0.006. The source, therefore, appears to have
faded, with a power-law index, alpha = 1.4 +0.8/-0.9. However, we cannot
rule out a constant source at this time, so cannot categorically confirm
this is an X-ray afterglow.
This is an official product of the Swift-XRT team.
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