TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4825 SUBJECT: GRB 060223B: Swift-BAT refined analysis DATE: 06/02/24 03:13:31 GMT FROM: Hans Krimm at NASA-GSFC E. Fenimore (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (ISAS), J. Tueller (GSFC) report on behalf of the Swift-BAT team: Using the data set from T-302 to T+110 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060223B (trigger #192152) (Cummings, et al., GCN 4821). The BAT ground-calculated position is (RA,Dec) = 254.240, -30.820 deg {16h 56m 57.7s, -30d 49' 10.8"} (J2000) +- 0.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%. The mask-weighted light curve shows a single broad peak from T-8 to T+6 with several subpeaks on top. There is no obvious spectral evolution visible. In the lowest energy band, low-level emission extends out to T+50 secs. T90 (15-350 keV) is 10.2 +- 1 sec (estimated error including systematics). Due to a preplanned slew, the BAT FOV moved away from the burst at about T+110 sec, and no information is available about any possible extended emission after that time. The time-averaged spectrum from T-7.0 to T+4.9 is best fit by a simple power-law model. The power-law index of the time-averaged spectrum is 1.49 +- 0.07. The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+3.0 sec in the 15-150 keV band is 2.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.