[vsnet-grb-info 16245] GRB 150302A: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17526
SUBJECT: GRB 150302A: Swift detection of a burst
DATE:    15/03/02 05:56:18 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

A. Y. Lien (GSFC/UMBC), M. M. Chester (PSU),
M. De Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA),
D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the
Swift Team:

At 05:42:36 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150302A (trigger=633237).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 175.508, +36.827 which is 
   RA(J2000) = 11h 42m 02s
   Dec(J2000) = +36d 49' 37"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single complex peak
structure with a duration of about 30 sec.  The peak count rate
was ~800 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 05:44:17.5 UT, 100.9 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 175.5314, 36.8110 which is equivalent to:
   RA(J2000)  = +11h 42m 7.54s
   Dec(J2000) = +36d 48' 39.6"
with an uncertainty of 5.9 arcseconds (radius, 90% containment). This
location is 88 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

UVOT took a finding chart exposure of	2 seconds with the White filter 
starting 109 seconds after the BAT trigger. No credible afterglow
candidate has  been found in the initial data products. Results from
the 2.7'x2.7' sub-image are not available at this time. Results from the
list of sources  generated on-board are not available at this time. No
correction has been made  for the expected extinction corresponding to
E(B-V) of 0.02. 

Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)