GRB 060109: Swift Detection of a long burst
TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 4455
SUBJECT: GRB 060109: Swift Detection of a long burst
DATE: 06/01/09 17:31:48 GMT
FROM: Jay R. Cummings at NASA/GSFC/Swift jayc@milkyway.gsfc.nasa.gov
M. De Pasquale (MSSL), S. Barthelmy (GSFC), A. Beardmore (U. Leicester), J. Cummings (GSFC/ORAU), N. Gehrels (GSFC), M.R. Goad (U. Leicester), O. Godet (U. Leicester), J. Kennea (PSU), H. Krimm (GSFC/USRA), F. Marshall (GSFC), K. Page (U. Leicester), D. Palmer (LANL), T. Sakamoto (GSFC), on behalf of the Swift Team:
At 16:54:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060109 (trigger=176620). The BAT on-board calculated location is RA,Dec 282.710, +31.989 {18h 50m 50s, +31d 59′ 22″} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 10 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the burst at 16:56:22 UT, 101 sec after the BAT trigger. A bright (0.2-10 keV flux of 4.8e-09 erg/cm2/sec), fading, uncatalogued source was found by the on-board centroiding algorithm at
RA(J2000)= 18h 50m 43.9s
DEC(J2000)= +31d 59′ 34.7″
with an uncertainty of 5.8 arcsec radius (90% containment). This uncertainty includes a systematic error of about 5 arcsec in the on-board calculated positions due to the XRT boresight offset. This position lies 84 arcsec from the centre of the BAT error circle.
UVOT took a finding chart exposure of 200 seconds with the V filter starting 104 sec 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 19.0 mag. No correction has been made for the expected visual extinction of about 0.5 magnitudes.
