TITLE: GCN CIRCULAR NUMBER: 30917 SUBJECT: GRB 210930A: Swift-BAT refined analysis DATE: 21/10/01 18:22:49 GMT FROM: Amy Lien at GSFC <amy.y.lien@nasa.gov> H. A. Krimm (NSF), S. D. Barthelmy (GSFC), V. D'Elia (SSDC & INAF-OAR), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), 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+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210930A (trigger #1075565) (D'Elia et al., GCN Circ. 30897). The BAT ground-calculated position is RA, Dec = 197.415, 48.630 deg which is RA(J2000) = 13h 09m 39.5s Dec(J2000) = +48d 37' 47.1" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single-pulse structure that starts at ~T+6 s, peaks at ~T+9 s, and ends at ~T+20 s. T90 (15-350 keV) is 11.81 +- 1.94 sec (estimated error including systematics). The time-averaged spectrum from T+5.84 to T+19.24 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.58 +- 0.19. The fluence in the 15-150 keV band is 4.0 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+8.40 sec in the 15-150 keV band is 0.7 +- 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/1075565/BA/