GCN Circular 45770

Subject

GRB 260925A: Swift-BAT refined analysis

Event

GRB 260925A

Date

2026-09-27T16:43:21Z (2 hours ago)

From

Amy <yarleen@gmail.com>

Via

D. Sadaula (GSFC/UMBC), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC),
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), T. Sakamoto (AGU) (i.e. the Swift-BAT team):

Using the data set from T-119 to T+723 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 260925A (trigger #1513316)
(Ambrosi et al., GCN Circ. 45739Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 132.475, 24.972 deg which is
   RA(J2000)  =  08h 49m 54.0s
   Dec(J2000) = +24d 58' 18.5"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The
partial coding was 100%.

The mask-weighted light curve shows a weak pulse that starts at ~T0, peaks
at ~T+1 s, and end at ~T+3 s. The pulse is potentially followed by some
weak tail emission that lasts till ~T+40 s.  T90 (15-350 keV) is 35.42 +-
10.55 sec (estimated error including systematics).

The time-averaged spectrum from T+0.48 to T+40.41 sec is best fit by a
simple power-law model.  The power law index of the time-averaged spectrum
is 1.60 +- 0.44.  The fluence in the 15-150 keV band is 2.4 +- 0.7 x 10^-07
erg/cm2. The 1-sec peak photon flux measured from T+1.10 sec in the 15-150
keV band is 0.6 +- 0.1 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/1513316

Previous Circular