TITLE: GCN CIRCULAR NUMBER: 12173 SUBJECT: GRB 110719A: Swift detection of a burst DATE: 11/07/19 06:22:14 GMT FROM: David Palmer at LANL T. Sakamoto (NASA/UMBC), A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC), M. De Pasquale (UCL-MSSL), C. Guidorzi (U Ferrara), O. M. Littlejohns (U Leicester), C. B. Markwardt (NASA/GSFC), S. R. Oates (UCL-MSSL), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), A. Rowlinson (U Leicester), C. J. Saxton (UCL-MSSL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 06:09:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110719A (trigger=457553). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 24.564, +34.572 which is RA(J2000) = 01h 38m 15s Dec(J2000) = +34d 34' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single noisy FRED structure with a duration of about 50 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~T-1 sec after the trigger. The XRT began observing the field at 06:11:03.1 UT, 111.3 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 24.5799, +34.5869 which is equivalent to: RA(J2000) = 01h 38m 19.17s Dec(J2000) = +34d 35' 12.8" with an uncertainty of 5.6 arcseconds (radius, 90% containment). This location is 71 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 150 seconds with the White filter starting 121 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. 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 0.04. Burst Advocate for this burst is T. Sakamoto (Taka.Sakamoto AT nasa.gov). 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.)