TITLE: GCN CIRCULAR NUMBER: 7264 SUBJECT: GRB 080207: Swift detection of a burst DATE: 08/02/07 21:48:14 GMT FROM: Scott Barthelmy at NASA/GSFC J. L. Racusin (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), P. J. Brown (PSU), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), S. D. Hunsberger (PSU), J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), R. L. C. Starling (U Leicester), M. C. Stroh (PSU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 21:30:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080207 (trigger=302728). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 207.513, +7.514 which is RA(J2000) = 13h 50m 03s Dec(J2000) = +07d 30' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This was an image-trigger, so the TDRSS lightcurve show little activity. The XRT began observing the field at 21:32:25 UT, 124 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 207.5117, +7.5018 which is RA(J2000) = 13h 50m 02.8s Dec(J2000) = 07d 30' 06.4" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 44 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 8.2e-09 erg/cm2/s (0.2-10 keV). UVOT took a finding chart exposure of 55 seconds with the White (160-650 nm) filter starting 140 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 3 sigma upper limit at the XRT position is white > 20. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is J. L. Racusin (racusin AT astro.psu.edu). 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.)