TITLE: GCN CIRCULAR NUMBER: 11776 SUBJECT: GRB 110305A: Swift-BAT refined analysis DATE: 11/03/05 14:24:03 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (GSFC), D. Grupe (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 110305A (trigger #448229) (Grupe, et al., GCN Circ. 11773). The BAT ground-calculated position is RA, Dec = 260.877, -15.810 deg which is RA(J2000) = 17h 23m 30.4s Dec(J2000) = -15d 48' 37.6" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 22%. The mask-weighted light curve shows a single pulse starting at ~T-1 sec and ending at ~T+12 sec. T90 (15-350 keV) is 12.0 +- 2.2 sec (estimated error including systematics). The time-averaged spectrum from T-0.9 to T+12.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.62 +- 0.19. The fluence in the 15-150 keV band is 8.0 +- 1.0 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+6.06 sec in the 15-150 keV band is 1.2 +- 0.3 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/448229/BA/