TITLE: GCN CIRCULAR NUMBER: 6821 SUBJECT: GRB 070923, Swift-BAT refined analysis DATE: 07/09/24 10:33:31 GMT FROM: Hans Krimm at NASA-GSFC J. Cummings (GSFC/UMBC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), M. C. Stroh (PSU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+230 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070923 (trigger #292004) (Stroh, et al., GCN Circ. 6818). The BAT ground-calculated position is RA, Dec = 184.623, -38.294 deg which is RA(J2000) = 12h 18m 29.5s Dec(J2000) = -38d 17' 38" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 75%. The mask weighted light curve shows a single peak of duration ~50 msec. T90 (15-350 keV) is 0.05 +- 0.01 sec (estimated error including systematics). The time-averaged spectrum from T+0.16 to T+0.37 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.02 +- 0.29. The fluence in the 15-150 keV band is 5.0 +- 0.9 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.40 sec in the 15-150 keV band is 2.4 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level.