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GCN Circular 5699

GRB 061006: Swift detection of a burst
2006-10-06T17:13:38Z (18 years ago)
David Palmer at LANL <>
P. Schady (MSSL-UCL), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC),
N. Gehrels (NASA/GSFC), C. Guidorzi (Univ Bicocca&INAF-OAB),
S. T. Holland (GSFC/USRA), S. D. Hunsberger (PSU),
V. Mangano (INAF-IASFPA), D. C. Morris (PSU),
P. T. O'Brien (U Leicester), C. Pagani (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL),
S. B. Pandey (UCL-MSSL), J. L. Racusin (PSU),
P. Romano (Univ. Bicocca & INAF-OAB), G. Sato (GSFC/ISAS),
M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester),
D. E. Vanden Berk (PSU) and H. Ziaeepour (UCL-MSSL) report on behalf
of the Swift Team:

At 16:45:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 061006 (trigger=232585).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA,Dec 111.090, -79.202 {07h 24m 22s, -79d 12' 05"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a large peak about 
5 seconds long during the pre-planned slew immediately preceding the start 
of the 64-second image in which the burst was found.  The peak count rate 
was ~5500 counts/sec (15-350 keV), at ~24 sec before the trigger. 

The XRT began taking data at 16:48:13 UT, 143 seconds after the BAT
trigger. The XRT on-board centroid algorithm did not find a source in
the image, but ground analysis of the data found a faint source at a
position of RA, Dec = 07h 24m 06.47s, -79d 11' 54.5" (J2000),  with
an estimated error radius of 8 arcsec (90% containment, including
boresight uncertainties). This is 44 arcsec from the BAT position. 

UVOT took a finding chart exposure of 400 seconds with the V filter
starting 140 seconds after the BAT trigger. 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 BAT 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 1.1 magnitudes.
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