TITLE: GCN CIRCULAR NUMBER: 23286 SUBJECT: GRB 180930A: Swift-BAT refined analysis DATE: 18/10/01 18:21:40 GMT FROM: Hans Krimm at NSF/NASA-GSFC S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), A. Tohuvavohu (PSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180930A (trigger #864584) (Tohuvavohu, et al., GCN Circ. 23279). The BAT ground-calculated position is RA, Dec = 76.894, -25.124 deg which is RA(J2000) = 05h 07m 34.6s Dec(J2000) = -25d 07' 25.6" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 87%. The mask-weighted light curve shows a single episode of weak emission from T-4 sec to T+4 sec with several peaks. T90 (15-350 keV) is 6.80 +- 0.95 sec (estimated error including systematics). The time-averaged spectrum from T-3.24 to T+4.20 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.86 +- 0.28. The fluence in the 15-150 keV band is 2.1 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.14 sec in the 15-150 keV band is 0.9 +- 0.2 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/864584/BA/