TITLE:   GCN CIRCULAR
NUMBER:  40765
SUBJECT: GRB 250615A: Swift-BAT refined analysis
DATE:    25/06/18 02:48:55 GMT
FROM:    Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>

S. D. Barthelmy (GSFC), S. Dichiara (PSU), 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),
T. Parsotan (GSFC), 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 250615A (trigger #1324646)
(Dichiara, et al., GCN Circ. 40736).  The BAT ground-calculated position is
RA, Dec = 290.384, 4.679 deg which is
   RA(J2000)  =  19h 21m 32.1s
   Dec(J2000) = +04d 40' 44.0"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 56%.

The mask-weighted light curve shows a complex structure that
starts at T-5 sec, peaks at T+5 sec, and ends at T+77 sec.
T90 (15-350 keV) is 52.5 +- 10.3 sec (estimated error including systematics).

The time-averaged spectrum from -5.2 to 77.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.22 +- 0.08.  The fluence in the 15-150 keV band is 3.8 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.29 sec in the 15-150 keV band
is 4.1 +- 0.3 ph/cm2/sec.  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/1324646