TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5534 SUBJECT: GRB 060906, Swift-BAT refined analysis DATE: 06/09/06 15:40:49 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMD), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), J.L. Racusin (PSU), 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 060906 (trigger #228316) (Racusin, et al., GCN Circ. 5528). The BAT ground-calculated position is RA,Dec = 40.710, 30.356 deg {2h 42m 50.4s, 30d 21' 21.3"} (J2000) +- 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 45%. This burst started at ~T-50 sec while the spacecraft was still slewing between regularly scheduled follow-up targets. The initial emission is a broad peak of roughly constant flux. It returns to background level at ~T-4 sec and then the peak which BAT actually triggerred on starts. It peaks at T~T+4 sec at a level about half of the initial broad peak. T90 (15-350 keV) is 43.6 +- 1 sec (estimated error including systematics). Because most of the burst happened during slewing, our standard processing for the spectral, flux, and fluence results are not appropriate. We will issue another circular with those results when they become available.