GCN Circular 33523

A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), M. J. Moss (GWU),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230325A (trigger #1161390)
(Moss, et al., GCN Circ. 33516
GCN 33516
David Palmer at LANL  <palmer@lanl.gov>
GRB 230325A: Swift detection of a burst
).  The BAT ground-calculated position is
RA, Dec = 296.854, -46.067 deg which is
   RA(J2000)  =  19h 47m 24.9s
   Dec(J2000) = -46d 03' 59.8"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 48%.

The mask-weighted light curve shows a main pulse with a FRED shape, from
approximately T+0 to T+8 seconds.  This is preceded by some precursor emission
starting around T-10 sec, and some low-level emission out to about T+40 sec.
The spacecraft slewed away from the burst location around T+620 seconds.
T90 (15-350 keV) is 38.05 +- 11.56 sec (estimated error including systematics).

The time-averaged spectrum from T-8.55 to T+41.70 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.82 +- 0.18.  The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.07 sec in the 15-150 keV band
is 3.3 +- 0.4 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1161390/BA/