TITLE: GCN CIRCULAR NUMBER: 29199 SUBJECT: GRB 201229A: Swift-BAT refined analysis DATE: 20/12/29 23:12:48 GMT FROM: Amy Lien at 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), B. Sbarufatti (PSU) 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 201229A (trigger #1015088) (Sbarufatti et al., GCN Circ. 29192). The BAT ground-calculated position is RA, Dec = 210.692, 48.209 deg which is RA(J2000) = 14h 02m 46.1s Dec(J2000) = +48d 12' 33.0" with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 26%. The mask-weighted light curve shows a multi-peaked structure that starts at ~T-45 s and ends at ~T+15 s. There is a weak pulse occurring at ~T-40 s, followed by the main peak at ~T0. T90 (15-350 keV) is 53.3 +- 4.6 sec (estimated error including systematics). The time-averaged spectrum from T-44.43 to T+13.62 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.40 +- 0.29. The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.41 sec in the 15-150 keV band is 1.7 +- 0.4 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/1015088/BA/