TITLE: GCN CIRCULAR NUMBER: 16546 SUBJECT: GRB 140709A: Swift detection of a burst DATE: 14/07/09 01:28:06 GMT FROM: David Palmer at LANL L. M. Z. Hagen (PSU), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 01:13:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140709A (trigger=603810). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 304.639, +51.223 which is RA(J2000) = 20h 18m 33s Dec(J2000) = +51d 13' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several peaks with a total duration of about 80 sec. The peak count rate was ~2800 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 01:15:04.0 UT, 82.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 304.66332, 51.22316 which is equivalent to: RA(J2000) = 20h 18m 39.20s Dec(J2000) = +51d 13' 23.4" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 54 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. No spectrum from the promptly downlinked event data is yet available to determine the column density. The initial flux in the 2.5 s image was 1.01e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 92 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. Results from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.40. Burst Advocate for this burst is L. M. Z. Hagen (lea.zernow.hagen AT gmail.com). 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.)