TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5395 SUBJECT: GRB 060804: Refined analysis of the Swift-BAT burst DATE: 06/08/04 18:00:12 GMT FROM: Scott Barthelmy at NASA/GSFC J. Tueller (GSFC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), M. Koss (GSFC/UMD), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), H. Z. Ziaeepour (UCL-MSSL) on behalf of the Swift-BAT team: Using the data set from T-240 to T+800 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060804 (trigger #222546) (Ziaeepour, et al., GCN Circ. 5394). The BAT ground-calculated position is RA,Dec = 112.216, -27.228 deg {7h 28m 51.8s, -27d 13' 41.8"} (J2000) +- 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 18%. The mask-weighted lightcurve shows two overlapping peaks. The first starts at T-14 sec and peaking at T-10 sec. The second peaks at T+4 sec. T90 (15-350 keV) is 16 +- 2 sec (estimated error including systematics). The time-averaged spectrum from T-12.3 to T+5.5 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.78 +- 0.28. The fluence in the 15-150 keV band is 5.1 +- 0.9 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+4.46 sec in the 15-150 keV band is 1.2 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.