[vsnet-grb-info 13754] Trigger 565443: Swift detection of a burst from SGR J1745-29

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15069
SUBJECT: Trigger 565443: Swift detection of a burst from SGR J1745-29
DATE:    13/08/05 02:43:52 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at milkyway.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC),
N. Gehrels (NASA/GSFC), V. Mangano (PSU),
C. J. Mountford (U Leicester), D. M. Palmer (LANL) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 02:09:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a burst consistent with the location of the Soft Gamma
Repeater SGR J1745-29.  Swift slewed immediately
to the burst. The BAT on-board calculated location is 
RA, Dec 266.420, -29.004 which is 
   RA(J2000)  =  17h 45m 41s
   Dec(J2000) = -29d 00' 14"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single short
soft peak with a duration of 64 ms.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 02:10:11.0 UT, 61.2 seconds after
the BAT trigger. Using promptly downlinked data we detect several x-ray
sources as expected for the Galactic Center region.  Further analysis 
using the full data will be required to identify the source of this event. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 66 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. 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 large, but uncertain extinction expected. 

We believe that this is further activity from the SGR J1745-29 source
which BAT last detected on June 7 of this year.  (The Chandra location
of this source is given in ATEL #5032.)