TITLE: GCN CIRCULAR NUMBER: 25953 SUBJECT: GRB 191004A: Swift-BAT refined analysis DATE: 19/10/05 03:50:01 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), S. B. Cenko (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 191004A (trigger #927825) (Cenko, et al., GCN Circ. 25945). The BAT ground-calculated position is RA, Dec = 31.716, -36.932 deg, which is RA(J2000) = 02h 06m 51.8s Dec(J2000) = -36d 55' 54.0" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 26%. The mask-weighted light curve has two overlapping peaks starting at ~T-0.2 sec, peaking at ~T_zero, and ending at ~3.1 sec. T90 (15-350 keV) is 2.44 +- 0.08 sec (estimated error including systematics). The time-averaged spectrum from T-0.09 to T+2.58 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.35 +- 0.08. The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.09 sec in the 15-150 keV band is 7.8 +- 0.5 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/927825/BA/