TITLE:   GCN CIRCULAR
NUMBER:  5675
SUBJECT: GRB 061002: Swift detection of a burst
DATE:    06/10/02 01:34:04 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J, K. C. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC),
S. D. Hunsberger (PSU), F. E. Marshall (NASA/GSFC),
K. M. McLean (LANL/UTD), K. L. Page (U Leicester),
D. M. Palmer (LANL) and M. Stamatikos (NASA/ORAU) report on behalf of
the Swift Team:

At 01:03:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 061002 (trigger=231974).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA,Dec 220.346, +48.736 {14h 41m 23s, +48d 44' 11"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a weak peak with a
duration of about 20 sec.  The peak count rate
was ~500 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began taking data at 01:05:41 UT, 132 seconds after the BAT
trigger. The XRT on-board centroid algorithm did not find a source in
the image, but ground analysis reveals a faint, probably fading source
at RA, Dec = 14h 41m 23.62s, +48d 44' 23.4" (J2000) with an estimated
uncertainty of 15 arcsec radius (90% containment). This is 14.9
arcsec from the BAT position. 

UVOT took a finding chart exposure of 400 seconds with the V filter
starting 128 seconds after the BAT trigger. No afterglow candidate
has been found in the initial data products. The 2.7'x2.7' sub-image
covers 25% of the BAT error circle and 100% of the XRT error circle. 
The 3-sigma upper limit  is about 19.0 mag. The 8'x8'region
for the list of sources generated on-board covers 100% of the BAT
error circle. No correction has been made for the expected extinction
of about 0.1 magnitudes. 

---APPENDED NEW UVOT PARAGRAPH---

UVOT took a finding chart exposure of 400 seconds with the V filter starting
128 seconds after the BAT trigger. No afterglow candidate has been found in the
initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error
circle. The typical 3-sigma upper limit has been about 18.5 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 extinction of about 0.1 magnitudes.