GRB 060111: Swift detection of a burst
TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 4479
SUBJECT: GRB 060111: Swift detection of a burst
DATE: 06/01/11 05:05:37 GMT
FROM: Scott Barthelmy at NASA/GSFC Scott@lheamail.gsfc.nasa.gov
S. Zane (MSSL-UCL), S. Barthelmy (GSFC), A. Beardmore (U Leicester), A. J. Blustin (UCL-MSSL), D. Burrows (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), M. Goad (U Leicester), J. Kennea (PSU), C. Markwardt (GSFC/UMD), F. Marshall (GSFC), D. Palmer (LANL) on behalf of the Swift team:
At 04:23:06 UT, Swift-BAT triggered and located GRB 060111 (trigger=176818). The spacecraft slewed immediately. The BAT on-board calculated location is RA,Dec 276.212d,+37.602d {18h 24m 51s,+37d 36′ 08″} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows a single peak structure with a total duration of ~20 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 04:24:12 UT (66 sec after the burst). The instrument found a bright, variable, uncataloged X-ray source located at:
RA(J2000) = 18h 24m 48.9s
Dec(J2000) = +37d 36′ 21″
This location is 27.4 arcseconds from the BAT position. The estimated uncertainty is 8 arcseconds (90% confidence radius), including about 5 arcseconds systematic error due to an XRT boresight offset not currently corrected on-board. The initial flux was 8E-10 ergs/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 200 seconds with the V filter starting 72 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7’x2.7′ sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 18th mag. The 8’x8′ region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected visual extinction of about 0.1 magnitudes.
We are currently in the portion of the orbits where the spacecraft does not pass over the Malindi downlink station. Therefore, it will be at least 7 hours before we have access to the full data set for the refined analyses.
