TITLE: GCN CIRCULAR NUMBER: 30429 SUBJECT: GRB 210708B: Swift-BAT refined analysis DATE: 21/07/09 10:39:56 GMT FROM: Hans Krimm at NSF/NASA-GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (PSU), T. N. Ukwatta (LANL) (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 210708B (trigger #1059494) (Sbarufatti, et al., GCN Circ. 30417). The BAT ground-calculated position is RA, Dec = 142.594, 14.523 deg which is RA(J2000) = 09h 30m 22.5s Dec(J2000) = +14d 31' 22.6" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 74%. The mask-weighted light curve shows a broad peak with some sub-structure. Emission begins around T-100 sec, peaks near the trigger time and decays to background by T+200 sec. The burst position was not in the field of view of the BAT until about T-150 sec. T90 (15-350 keV) is 298.43 +- 47.32 sec (estimated error including systematics). The time-averaged spectrum from -99.8 to 263.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.62 +- 0.26. The fluence in the 15-150 keV band is 2.2 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+2.84 sec in the 15-150 keV band is 0.0 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. We note that in the original GCN circular, the event was described as a possible burst. Analysis of the full data set shows that the event is indeed a GRB. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1059494/BA/