TITLE: GCN CIRCULAR NUMBER: 41730 SUBJECT: GRB 250904A: Swift-BAT refined analysis DATE: 25/09/05 21:28:22 GMT FROM: D. R. Sadaula at NASA GSFC <dev.r.sadaula@nasa.gov> D. M. Palmer (LANL), 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), 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 250904 A (trigger #1347179) (Salvaggio, et al., GCN Circ. 41704). The BAT ground-calculated position is RA, Dec = 84.377, 3.575 deg which is RA(J2000) = 05h 37m 30.5s Dec(J2000) = +03d 34' 29.9" with an uncertainty of 1.0 arcmin (radius, sys+stat, 90% containment). The partial coding was 100%. The BAT light curve showed a complex structure with a duration of about 50 sec. T90 (15-350 keV) is 37.11 +- 13.89 sec (estimated error including systematics). The time-averaged spectrum from T-19.68 to T+54.44 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.40 +- 0.11. The fluence in the 15-150 keV band is 1.7 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+5.11 sec in the 15-150 keV band is 1.1 +- 0.2 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/1347179 View this GCN Circular online at https://gcn.nasa.gov/circulars/41730. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...