{
  "bibcode": "2019GCN.25945....1C",
  "body": "S. B. Cenko (GSFC), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), A. D'Ai (INAF-IASFPA),\nV. D'Elia (SSDC), J.D. Gropp (PSU), N. J. Klingler (PSU),\nS Laha (CRESST/GSFC/UMD), A. Y. Lien (GSFC/UMBC),\nF. E. Marshall (NASA/GSFC), M. J. Moss (GWU),\nK. L. Page (U Leicester), B. Sbarufatti (PSU) and\nA. Tohuvavohu (Toronto) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 18:07:02 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 191004A (trigger=927825).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 31.721, -36.932 which is \n   RA(J2000)  =  02h 06m 53s\n   Dec(J2000) = -36d 55' 53\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a double-peaked\nstructure with a duration of about 5 sec.  The peak count rate\nwas ~8000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 18:08:24.2 UT, 81.5 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 31.66950, -36.93368 which is equivalent\nto:\n   RA(J2000)  = 02h 06m 40.68s\n   Dec(J2000) = -36d 56' 01.2\"\nwith an uncertainty of 3.6 arcseconds (radius, 90% containment). This\nlocation is 148 arcseconds from the BAT onboard position, within the\nBAT error circle. This position may be improved as more data are\nreceived; the latest position is available at\nhttp://www.swift.ac.uk/sper. No spectrum from the promptly downlinked\nevent data is yet available to determine the column density. \n\nUVOT took a finding chart exposure of 150 seconds with the White\nfilter  starting 84 seconds after the BAT trigger. Results from the\nlist of sources generated on-board shows an optical source consistent\nwith the XRT position.  Because there was not automatic aspect\nsolution for the image,  the precise position and magnitude will be\nreported later.  The 2.7'x2.7' sub-image covers none of the XRT error\ncircle.  No correction has been made for the expected  extinction\ncorresponding to E(B-V) of 0.01. \n\nBurst Advocate for this burst is S. B. Cenko (brad.cenko AT 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/)",
  "circularId": 25945,
  "createdOn": 1570213853000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 191004A: Swift detection of a burst with an optical detection",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 191004A"
}