TITLE: GCN CIRCULAR NUMBER: 18648 SUBJECT: GRB 151127A: Swift-BAT refined analysis DATE: 15/11/27 16:48:26 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), A. D'Ai (INAF-IASFPA), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), 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-60 to T+243 sec from recent telemetry downlinks, we report further analysis of BAT GRB 151127A (trigger #665268) (D'Ai, et al., GCN Circ. 18643). The BAT ground-calculated position is RA, Dec = 19.664, -82.762 deg, which is RA(J2000) = 01h 18m 39.4s Dec(J2000) = -82d 45' 42.1" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 96%. The mask-weighted light curve shows a single spike starting at T_zero and ending at ~T+0.25 sec. T90 (15-350 keV) is 0.19 +- 0.04 sec (estimated error including systematics). The time-averaged spectrum from T+0.016 to T+0.220 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.33. The fluence in the 15-150 keV band is 2.3 +- 0.6 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.38 sec in the 15-150 keV band is 0.4 +- 0.1 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/665268/BA/