TITLE: GCN CIRCULAR NUMBER: 17981 SUBJECT: GRB 150626B, Swift-BAT refined analysis DATE: 15/06/28 20:03:41 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), L. M. McCauley (PSU), 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-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150626B (trigger #646786) (McCauley et al., GCN Circ. 17966). The BAT ground-calculated position is RA, Dec = 187.627, 66.794 deg which is RA(J2000) = 12h 30m 30.6s Dec(J2000) = +66d 47' 39.6" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a single-peaked structure that starts at ~T-15 s, peaks at ~T+1 s, and ends at ~T+30 s. T90 (15-350 keV) is 48.0 +- 22.6 sec (estimated error including systematics). The time-averaged spectrum from T-15.6 to T+32.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.36 +- 0.21. The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+7.94 sec in the 15-150 keV band is 0.6 +- 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/646786/BA/