{
  "bibcode": "2018GCN.22930....1M",
  "body": "F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),\nA. D'Ai (INAF-IASFPA), V. D'Elia (ASDC), P. A. Evans (U Leicester),\nJ. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC)\nand K. L. Page (U Leicester) report on behalf of the Neil Gehrels\nSwift Observatory Team:\n\nAt 10:52:00 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 180709A (trigger=846868).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 38.119, +60.372 which is \n   RA(J2000) = 02h 32m 29s\n   Dec(J2000) = +60d 22' 18\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a multi-peaked\nstructure with a duration of about 30 sec.  The peak count rate\nwas ~800 counts/sec (15-350 keV), at ~6 sec after the trigger. \n\nThe XRT began observing the field at 10:53:45.0 UT, 104.8 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source with an enhanced position: RA, Dec\n38.1178, 60.3490 which is equivalent to:\n   RA(J2000)  = 02h 32m 28.27s\n   Dec(J2000) = +60d 20' 56.5\"\nwith an uncertainty of 2.1 arcseconds (radius, 90% containment). This\nlocation is 82 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position may be improved as more data are received;\nthe latest position is available at http://www.swift.ac.uk/sper. No\nspectrum from the promptly downlinked event data is yet available to\ndetermine the column density. \n\nThe initial flux in the 2.5 s image was 6.60e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 114 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 100% of\nthe XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nXRT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the large, but uncertain, extinction expected. \n\nBurst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). \nPlease contact the BA by email if you require additional information\nregarding Swift followup of this burst. In extremely urgent cases, after\ntrying the Burst Advocate, you can contact the Swift PI by phone (see\nSwift TOO web site for information: http://www.swift.psu.edu/too.html.)",
  "circularId": 22930,
  "createdOn": 1531134685000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 180709A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 180709A"
}