TITLE: GCN CIRCULAR NUMBER: 29467 SUBJECT: GRB 210210A: Swift-BAT refined analysis DATE: 21/02/10 22:32:30 GMT FROM: Hans Krimm at NSF/NASA-GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), 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 210210A (trigger #1031728) (Laha, et al., GCN Circ. 29444). The BAT ground-calculated position is RA, Dec = 262.764, 14.657 deg which is RA(J2000) = 17h 31m 03.4s Dec(J2000) = +14d 39' 26.8" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 43%. The mask-weighted light curve shows a double-peaked structure running approximately from T-1 sec to T+7 sec. The first pulse peaks close to T+0 sec and the second pulse peaks at T+4.5 sec. T90 (15-350 keV) is 6.60 +- 0.59 sec (estimated error including systematics). The time-averaged spectrum from T-0.75 to T+6.93 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.53 +- 0.58, and Epeak of 19.9 +- 13.9 keV (chi squared 44.33 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 9.8 +- 0.8 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+4.21 sec in the 15-150 keV band is 7.0 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.46 +- 0.12 (chi squared 53.94 for 57 d.o.f.). 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/1031728/BA/