TITLE: GCN CIRCULAR NUMBER: 28179 SUBJECT: GRB 200729A: Swift-BAT refined analysis DATE: 20/07/30 18:22:38 GMT FROM: Amy Lien at GSFC H. A. Krimm (NSF), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), P. A. Evans (U Leicester), S. Laha (GSFC/UMBC), A. Y. Lien (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 200729A (trigger #984929) (Evans et al., GCN Circ. 28165). The BAT ground-calculated position is RA, Dec = 184.360, 45.571 deg which is RA(J2000) = 12h 17m 26.5s Dec(J2000) = +45d 34' 13.9" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%. The mask-weighted light curve shows a weak pulse that starts at ~T0, peaks at ~T+6 s, and ends at ~T+130 s. T90 (15-350 keV) is 122.0 +- 34.2 sec (estimated error including systematics). The time-averaged spectrum from T+0.54 to T+136.54 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.96 +- 0.27. The fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+5.54 sec in the 15-150 keV band is 0.7 +- 0.3 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/984929/BA/