TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4820 SUBJECT: GRB 060223: Swift-BAT refined analysis DATE: 06/02/23 19:34:30 GMT FROM: Scott Barthelmy at NASA/GSFC J. Cummings (GSFC/NRC), S. Barthelmy (GSFC), L. Barbier (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), 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 partial data set from T-300 to T+302 sec from telemetry downlinks, we report further analysis of BAT GRB 060223 (trigger #192059) (Cummings, et al., GCN 4813; Marshall et al, GCN 4814). The BAT ground-calculated position is RA,Dec = 55.188,-17.130 deg {3h 40m 45.1s, -17d 7' 46.6"} (J2000) +- 1.2 arcmin, (radius, sys+stat, 90% containment). The BAT error circle contains the afterglow detected by UVOT (GCN 4813). The partial coding was 69%. The mask-weighted light curve shows a single episode of emission from T-4 to T+10 sec. There is a possible broad, faint precursor at ~T-25 sec, but no significant emission after T+10 sec. T90 (15-350 keV) is 11 +- 2 sec (estimated error including systematics). The time-averaged spectrum from T-2.9 to T+10.0 is best fit by a simple power-law model. The power-law index of the time-averaged spectrum is 1.74 +- 0.12. The fluence in the 15-150 keV band is 6.8 +- 0.5 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+0.08 sec in the 15-150 keV band is 1.4 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. Given the redshift reported for this burst (Berger et al, GCN 4815), z = 4.41, we calculate Eiso = 2.82 10^52 ergs in the 81-812 keV band in the rest frame of the source.