TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4813 SUBJECT: GRB 060223: Swift detection of a burst DATE: 06/02/23 06:29:33 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (NASA/ORAU), S. D. Barthelmy (NASA/GSFC), P. T. Boyd (NASA/GSFC), D. N. Burrows (PSU), M. Capalbi (ASDC), M. M. Chester (PSU), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. Perri (ASDC) report on behalf of the Swift Team: At 06:04:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060223 (trigger=192059). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 55.216, -17.139 {03h 40m 52s, -17d 08' 19"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 15 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began taking data at 06:05:49 UT, 86 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image and no prompt position is available. We are waiting for down-linked data to detect and determine a position for the source. In response to the Swift/BAT trigger 192059, UVOT took a finding chart exposure of nominally 200 seconds with the V filter starting 86.5 seconds after the BAT trigger. There is a candidate afterglow in the sub-imagae and the list of sources generated on-board at (RA,DEC) (J2000) of (55.2065, -17.1301) with a 1-sigma error radius of about 1 arcsec. This position is 45.9 arcsec from the center of the BAT error circle. The estimated V magnitude is 17.6 with a 1-sigma error of about 0.5 mag.