TITLE: GCN CIRCULAR NUMBER: 9978 SUBJECT: Trigger 371210: Swift/BAT Triggered on IGR J17511-3057 DATE: 09/09/30 18:46:52 GMT FROM: David Burrows at PSU/Swift N. A. Lyons (U Leicester), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), M. M. Chester (PSU), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), P. Romano (INAF-IASFPA), A. Rowlinson (U Leicester), T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 18:31:56 UT, the Swift Burst Alert Telescope (BAT) located trigger 371210, which is the known source IGR J17511-3057. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 267.767, -30.979 which is RA(J2000) = 17h 51m 04s Dec(J2000) = -30d 58' 42" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is consistent with a type 1 thermonuclear X-ray burst, both in duration and because it appears only in the lowest energy band (15-25 keV). The XRT began observing the field at 18:33:07.8 UT, 71.2 seconds after the BAT trigger. Using promptly downlinked data we find a bright X-ray counterpart located at RA, Dec 267.78641, -30.96082 which is equivalent to: RA(J2000) = 17h 51m 8.74s Dec(J2000) = -30d 57' 39.0" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 88 arcseconds from the BAT onboard position, within the BAT error circle, and is consistent with the position obtained with Chandra (ATel #2215).