[vsnet-grb-info 2003] GRB 050820B: Swift XRT position
GCN Circulars
gcncirc at capella.gsfc.nasa.gov
Sun Aug 21 12:28:31 JST 2005
TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 3842
SUBJECT: GRB 050820B: Swift XRT position
DATE: 05/08/21 03:26:35 GMT
FROM: David Burrows at PSU/Swift <dxb15 at psu.edu>
D. N. Burrows (PSU) reports on behalf of the Swift XRT team:
The Swift BAT instrument triggered on GRB 050820B at 23:50:27.19 UT (GCN
3839, Page et al.). At that time, the source was within the Earth limb
constraint and the S/C was not able to slew immediately. Swift executed a
delayed slew at 0:17:37, while the observatory was in the South Atlantic
Anomaly. The XRT attempted to locate a bright source in its field of view,
but was not able to do so due to the delayed slew and to the presence of
many charged particle events in the image. XRT Photon-Counting mode
observations began at 00:28:3.6 (2256 s after the burst trigger), following
exit from the South Atlantic Anomaly and completion of pre-programmed XRT
engineering data collection. In analysis of engineering format (PASS1)
ground-processed data at the MOC, we find a faint, fading, uncataloged
X-ray source located at:
RA(J2000) = 09h 02m 24.6s
Dec(J2000) = -72d 38' 43"
with an estimated uncertainty of 8 arcseconds (90% containment
radius). This position is 25 arcseconds from the refined BAT position
reported in GCN 3840 (Fenimore et al.).
Further observations are in progress. Refined analysis will become
available following processing of the data through the Swift Data Center's
pipeline.
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