TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3856 SUBJECT: GRB 050822: Swift-BAT refined analysis DATE: 05/08/22 17:47:01 GMT FROM: Takanori Sakamoto at NASA/GSFC D. Hullinger (UMD), L. Angelini (GSFC-JHU), L. Barbier (GSFC), S. Barthelmy (GSFC), M. Chester (PSU), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC), on behalf of the Swift-BAT team: Using the full data set from the recent telemetry downlink, we report further analysis of Swift-BAT GRB 050822 (trigger #151486) (Blustin, et al., GCN 3849). The refined BAT ground position is (RA,Dec) = 51.098, -46.031 {03:24:19.2, -46:01:22.8} [deg; J2000] +-2 arcmin, (90% containment). This is 27 arc-seconds from the XRT position reported in GCN 3849. The partial coding was 44%. The light curve has two main peaks. The first peak starts from T0-4 sec, peaking at T0, and then ending at T0+20 sec with a gradual decay. The second peak contains multiple sub-peaks. It starts from T0+20 sec and ends at T0+75 sec. There is a smaller, somewhat softer peak from T+100 to T+104 seconds while Swift was pointing at the source and the XRT was taking data. T90 (15-350 keV) is (102 +- 2) seconds (estimated error including systematics). The power law index of the time-averaged spectrum is 2.5 +- 0.1. Thus, the time-averaged spectrum turns out to be soft. The fluence in the 15-350 keV band is (3.4 +- 0.3) x 10^-6 erg/cm2. The 1-s peak photon flux measured from T0+47.6 second in the 15-350 keV band is (2.9 +- 0.3) ph/cm2/s. All the quoted errors are at the 90% confidence level.