TITLE: GCN CIRCULAR NUMBER: 8236 SUBJECT: GRB 080915B, Swift-BAT refined analysis DATE: 08/09/15 19:49:30 GMT FROM: Scott Barthelmy at NASA/GSFC K. McLean (GSFC/UMD), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU), H. Ziaeepour (UCL-MSSL) (i.e. the Swift-BAT team): Using the data set from T-28 to T+930 sec from the recent telemetry downlink, we report further analysis of BAT GRB 080915B (trigger #324805) (Ziaeepour, et al., GCN Circ. 8234). The BAT ground-calculated position is RA, Dec = 213.088, -11.491 deg, which is RA(J2000) = 14h 12m 21.2s Dec(J2000) = -11d 29' 26.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 74%. The mask-weighted light curve shows a roughly symmetric peak starting at ~T-0.5 sec, peaking at ~T+0.6 sec, and ending at ~T+4.5 sec. T90 (15-350 keV) is 3.9 +- 0.7 sec (estimated error including systematics). The time-averaged spectrum from T-0.5 to T+6.1 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.48 +- 0.35, and Epeak of 42.3 +- 9.1 keV (chi squared 54.5 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 9.9 +- 0.6 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+0.18 sec in the 15-150 keV band is 8.5 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.02 +- 0.08 (chi squared 62.6 for 57 d.o.f.). 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/324805/BA/