TITLE: GCN CIRCULAR NUMBER: 9736 SUBJECT: GRB 090728: Swift-BAT refined analysis DATE: 09/07/29 20:08:49 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 090728 (trigger #358574) (Mangano, et al., GCN Circ. 9725). The BAT ground-calculated position is RA, Dec = 29.644, 41.632 deg which is RA(J2000) = 01h 58m 34.5s Dec(J2000) = +41d 37' 53.7" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 37%. The mask-weighted light curve shows a single pulse starting at ~T-10 sec, peaking at ~T+2 sec, and ending at ~T+70 sec. T90 (15-350 keV) is 59 +- 18 sec (estimated error including systematics). The time-averaged spectrum from T-5.0 to T+63.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.05 +- 0.26. The fluence in the 15-150 keV band is 1.0 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.25 sec in the 15-150 keV band is 1.0 +- 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/358574/BA/