TITLE: GCN CIRCULAR NUMBER: 9089 SUBJECT: GRB 090404: Swift-BAT refined analysis DATE: 09/04/04 23:48:55 GMT FROM: Scott Barthelmy at NASA/GSFC J. Tueller (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), T. N. Ukwatta (GWU), H. Ziaeepour (UCL-MSSL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 090404 (trigger #348428) (Ziaeepour, et al., GCN Circ. 9086). The BAT ground-calculated position is RA, Dec = 239.233, 35.518 deg, which is RA(J2000) = 15h 56m 55.8s Dec(J2000) = +35d 31' 03.4" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve shows at least 7 overlapping peaks starting at ~T-50 sec and ending at ~T+150 sec. T90 (15-350 keV) is 84 +- 14 sec (estimated error including systematics). The time-averaged spectrum from T-35.2 to T+94.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.32 +- 0.08. The fluence in the 15-150 keV band is 3.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+17.32 sec in the 15-150 keV band is 1.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/348428/BA/