GCN Circular 41167

T. Parsotan (GSFC), S. D. Barthelmy (GSFC), 
P. A. Evans (U Leicester), R. Gupta (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL),
D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 250725A (trigger #1336720)
(Evans, et al., GCN Circ. 41152
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 ).  The BAT ground-calculated position is
RA, Dec = 35.459, -82.786 deg which is 
   RA(J2000)  =  02h 21m 50.1s 
   Dec(J2000) = -82d 47' 10.4" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 34%.
 
The mask-weighted BAT light curve shows multi-peaked emission episode starting 
~T-2 sec, with a sharp rise and a structured decay extending over ~12 seconds. 
T90 (15-350 keV) is 9.58 +- 0.25 sec (estimated error including systematics).

The time-averaged spectrum from T-1.77 to T+9.50 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.81 +- 0.19, and
Epeak of 207.2 +- 105.6 keV (chi squared 38.63 for 56 d.o.f.).  For this model 
the total fluence in the 15-150 keV band is 5.0 +- 0.1 x 10^-06 erg/cm2 and
the 1-sec peak flux measured from T+0.06 sec in the 15-150 keV band
is 12.5 +- 0.6 ph/cm2/sec.  A fit to a simple power law gives a photon index of
1.15 +- 0.05 (chi squared 49.20 for 57 d.o.f.).
All the quoted errors are at the 90% confidence level.

The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1336720