TITLE: GCN CIRCULAR NUMBER: 30997 SUBJECT: GRB 211025A: Swift-BAT refined analysis DATE: 21/10/25 19:04:28 GMT FROM: Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov> C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J.D. Gropp (PSU), H. A. Krimm (NSF),S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), D. M. Palmer (LANL),T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+844 sec from the recent telemetry downlink, we report further analysis of BAT GRB 211025A (trigger #1081113) (Gropp, et al., GCN Circ. 30986). The BAT ground-calculated position is RA, Dec = 162.407, 31.506 deg which is RA(J2000) = 10h 49m 37.8s Dec(J2000) = +31d 30' 20.8" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single broad pulse beginning at T+0, peaking around T+50 sec and declining to background by T+150 sec. T90 (15-350 keV) is 103.5 +- 27.6 sec (estimated error including systematics). The time-averaged spectrum from T+12.32 to T+128.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.96 +- 0.28. The fluence in the 15-150 keV band is 7.7 +- 1.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+51.66 sec in the 15-150 keV band is 0.5 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1081113/BA/