TITLE: GCN CIRCULAR NUMBER: 17266 SUBJECT: GRB 150101A Swift-BAT refined analysis of the short hard burst DATE: 15/01/02 21:19:17 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings, 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), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec, we report further analysis of BAT GRB 150101A (trigger #623158) (Vargas, et al., GCN Circ. 17261). The BAT ground-calculated position is RA, Dec = 312.599, 36.669 deg which is RA(J2000) = 20h 50m 23.6s Dec(J2000) = +36d 40' 07.8" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 91%. The mask-weighted light curve shows a single peak. T90 (15-350 keV) is 0.060 +- 0.005 sec (estimated error including systematics). The time-averaged spectrum from T+0.0 to T+0.68 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.31. The fluence in the 15-150 keV band is (2.3 +- 0.5) x 10^-08 erg/cm2. The 1-sec peak photon flux measured from T-0.46 sec in the 15-150 keV band is 0.3 +- 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/623158/BA/