TITLE: GCN CIRCULAR NUMBER: 41167 SUBJECT: GRB 250725A: Swift-BAT refined analysis DATE: 25/07/25 16:18:21 GMT FROM: Rahul Gupta at NASA GSFC <rahul.gupta@nasa.gov> 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). 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/41167. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...