[vsnet-grb-info 3125] SGR 1900+14: Swift detection of an outburst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4962
SUBJECT: SGR 1900+14: Swift detection of an outburst
DATE:    06/04/14 05:06:39 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

A. D. Falcone (PSU), S. D. Barthelmy (GSFC), S. D. Hunsberger (PSU)
and D. M. Palmer (LANL) report on behalf of the Swift Team:

At 04:35:28 UT 14 Apr 06, the Swift Burst Alert Telescope (BAT)
triggered and located an outburst from SGR 1900+14 (trigger=205164). 
Swift slewed immediately to the burst. The BAT on-board calculated
location is RA,Dec 286.799, +9.322 {19h 07m 12s, +09d 19' 19"}
(J2000) with an uncertainty of 3 arcmin (radius, 90% containment,
including  systematic uncertainty), 37 arcseconds from the known
source location.  The BAT light curve shows a single spike with a
duration less than 256 msec. The peak count rate was ~3000 counts/sec
(15-350 keV), at ~0 sec after the trigger. This is the third burst of
comparable size from this source in the past three days. 

The XRT began taking data at 04:36:17 UT, 49 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. However, from the
initial light curve, it appears that XRT did detect photons from the
outburst. 

UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 53 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 the known position of SGR1900+14. 
 The list of sources is typically complete to about 18 mag. No
correction has been made for the large, but uncertain extinction
expected.