GCN Circular 5285

A. Moretti (INAF-OAB), S. D. Barthelmy (GSFC), P. T. Boyd (NASA/GSFC),
P. J. Brown (PSU), M. M. Chester (PSU), N. Gehrels (NASA/GSFC),
C. Guidorzi (Univ Bicocca&INAF-OAB), J. A. Kennea (PSU),
C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC),
K. M. McLean (LANL/UTD), C. Pagani (PSU), D. M. Palmer (LANL),
T. Sakamoto (NASA/ORAU), M. Stamatikos (NASA/ORAU) and
D. E. Vanden Berk (PSU) report on behalf of the Swift Team:

At 21:30:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060707 (trigger=217704).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA,Dec 357.079, -17.923 {23h 48m 19s, -17d 55' 21"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single FRED-like peak
at T_0 lasting about 30 sec.  There is a hard precusor at T-45 sec. 
The total duration is ~75 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began taking data at 21:32:20 UT, 122 seconds after the BAT
trigger.  The XRT on-board centroid algorithm did not find a source in the
image and no prompt position is available.  Down-linked
data show a bright source at RA(2000)=23 48 19.00  DEC(2000):-17 54 21.8
with an error circle of 3.8". This position is 60" from the BAT position. 

UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 126 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 ground-determined XRT 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 mag. No correction
has been made for the expected extinction corresponding to E(B-V) of
0.02.