TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5200 SUBJECT: GRB 060602B: Swift detection of a burst DATE: 06/06/03 00:53:33 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL-UCL), A. P. Beardmore (U Leicester), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), E. Rol (U Leicester) and G. Sato (GSFC/JSPS/USRA) report on behalf of the Swift Team: At 23:54:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060602B (trigger=213190). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 267.380, -28.109 {17h 49m 31s, -28d 06' 31"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 20 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at 7 sec after the trigger. The XRT began taking data at 23:55:56 UT, 83 seconds after the BAT trigger. We find a faint uncatalogued source in the first 246s of down-linked PC mode data at RA,Dec (J2000) = 17 49 31.7, -28 08 03.7 with an uncertainty of 3.9 arcsec (90% containment). This is 92 arcsec from the on-board BAT position. This source is not consistent with the BOOTES-IR candidate reported in GCN 5198. UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 89 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 18.5 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. We note that this is a crowded field and that a large, but uncertain extinction is expected.