TITLE: GCN CIRCULAR NUMBER: 7781 SUBJECT: GRB 080602: Swift detection of a burst DATE: 08/06/02 01:41:09 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), K. M. McLean (GSFC/UMD), K. L. Page (U Leicester), D. M. Palmer (LANL) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 01:30:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080602 (trigger=312958). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 19.173, -9.251 which is RA(J2000) = 01h 16m 41s Dec(J2000) = -09d 15' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed two well-separated peaks with a total duration of about 70 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~60 sec after the trigger. The XRT began observing the field at 01:32:19.7 UT, 111.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 19.1766, -9.2336 which is equivalent to: RA(J2000) = 01h 16m 42.3s Dec(J2000) = -09d 14' 00.9" with an uncertainty of 5.8 arcseconds (radius, 90% containment). This location is 63 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to assess possible redshift constraints using X-ray spectroscopy and the nH-z relation from Grupe et al. (2007). UVOT took a finding chart exposure of nominal 100 seconds with the White (160-650 nm) filter starting 123 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. Image catalog data are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)