TITLE: GCN CIRCULAR NUMBER: 11058 SUBJECT: GRB 100805A: Swift-BAT refined analysis DATE: 10/08/05 12:46:07 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), E. A. Hoversten (PSU), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 100805A (trigger #430957) (Hoversten, et al., GCN Circ. 11047). The BAT ground-calculated position is RA, Dec = 299.846, 52.618 deg, which is RA(J2000) = 19h 59m 23.0s Dec(J2000) = +52d 37' 05.8" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows a few overlapping weak peaks starting at ~T-1 sec, peaking at ~T+2 sec, and ending at ~T+20 sec. There is a possible 3-sigma peak at ~T+60 sec. T90 (15-350 keV) is 15.0 +- 3.0 sec (estimated error including systematics). The time-averaged spectrum from T-1.4 to T+17.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.76 +- 0.23. The fluence in the 15-150 keV band is 5.1 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.97 sec in the 15-150 keV band is 0.7 +- 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/430957/BA/