TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5621 SUBJECT: GRB 060926, Swift-BAT refined analysis DATE: 06/09/26 23:19:19 GMT FROM: Scott Barthelmy at NASA/GSFC J. Cummings (GSFC/UMBC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), S. T. Holland (GSFC/USRA), D. Hullinger (BYU-Idaho), 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), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the data set from T-119 to T+183 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060926 (trigger #231231) (Holland, et al., GCN Circ. 5612). The BAT ground-calculated position is RA,Dec = 263.925, 13.039 deg {17h 35m 41.9s, 13d 2' 21.5"} (J2000) +- 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 94%. The mask-weighted lightcuve shows a single FRED peak starting at T-1 sec, peaking at T+1 sec, and ending approximately at T+10 sec. T90 (15-350 keV) is 8.0 +- 0.1 sec (estimated error including systematics). The time-averaged spectrum from T-0.1 to T+8.6 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.54 +- 0.23. The fluence in the 15-150 keV band is 2.2 +- 0.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.38 sec in the 15-150 keV band is 1.1 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.