[vsnet-grb-info 19248] GRB 170325A, Swift-BAT detection of a short GRB

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20938
SUBJECT: GRB 170325A, Swift-BAT detection of a short GRB
DATE:    17/03/26 04:36:10 GMT
FROM:    David Palmer at LANL  <dmopalmer at gmail.com>

GRB 170325A, Swift-BAT detection of a short GRB
 
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), 
J. R. Cummings (CPI), N. Gehrels (GSFC),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
GRB 170325A was detected by Swift/BAT at 2017-03-25 07:56:57.95 UTC.  
Because the spacecraft was slewing at that time, there was no onboard triggers, 
and the burst was found later in the ground analysis in response to
Fermi-GBM trigger #512121423.

Using the data set from T-16 to T+92 sec from the recent telemetry downlink,
The BAT ground-calculated position is
RA, Dec = 127.483, 20.526 deg which is 
   RA(J2000)  =  08h 29m 55.9s 
   Dec(J2000) = +20d 31' 32.5" 
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
 
The mask-weighted light curve shows a single FRED-like pulse that
starts and peaks at ~T0, and ends at ~T+0.4 s. T90 (15-350 keV) is 0.3 +- 0.1 sec 
(estimated error including systematics).
 
The time-averaged spectrum from T+0.0 to T+0.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.06 +- 0.26.  The fluence in the 15-150 keV band is 8.8 +-1.3 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.30 sec in the 15-150 keV band
is 1.1 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.