TITLE: GCN CIRCULAR NUMBER: 17880 SUBJECT: GRB 150527A: Swift-BAT refined analysis DATE: 15/05/27 16:47:04 GMT FROM: Scott Barthelmy at NASA/GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), P. A. Evans (U Leicester), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), 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+711 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150527A (trigger #641698) (Evans, et al., GCN Circ. 17874). The BAT ground-calculated position is RA, Dec = 288.962, 4.195 deg, which is RA(J2000) = 19h 15m 50.9s Dec(J2000) = +04d 11' 41.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 99%. The mask-weighted light curves shows a multi-peak event starting at ~T-45 sec, with the brightest peak at ~T-14, and ending at T+25 sec. T90 (15-350 keV) is 112 +- 80 sec (estimated error including systematics). The time-averaged spectrum from T-111.44 to T+16.56 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.69 +- 0.10. The fluence in the 15-150 keV band is 3.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-7.94 sec in the 15-150 keV band is 0.3 +- 0.2 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/641698/BA/