TITLE: GCN CIRCULAR NUMBER: 5611 SUBJECT: GRB 060923C, Swift-BAT refined analysis DATE: 06/09/25 19:51:01 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060923 (trigger #230711) (Stamatikos, et al., GCN Circ. 5591; Barthelmy, et al., GCN Circ 5600). The BAT ground-calculated position is RA,Dec = 346.122, 3.943 deg {23h 4m 29.3s, 3d 56' 33.8"} (J2000) +- 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 17%. The mask-weighted lightcurve has a single long emision from T+0 to T+110 sec. T90 (15-350 keV) is 76 +- 2 sec (estimated error including systematics). The long duration and smooth profile of the lightcurve suggest, but do not prove, that this is a high redshift burst. The time-averaged spectrum from T+6.8 to T+90.7 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.27 +- 0.24. The fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+27.54 sec in the 15-150 keV band is 1.0 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level.