{
  "bibcode": "2017GCN.20446....1E",
  "body": "P.A. Evans (U Leicester), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), H. A. Krimm (CRESST/NSF/USRA),\nB. Mingo (U Leicester), P. T. O'Brien (U Leicester),\nB. Sbarufatti (INAF-OAB/PSU), R. L. C. Starling (U Leicester) and\nE. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team:\n\nAt 10:04:05 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 170113A (trigger=732526).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 61.648, -71.925, which is \n   RA(J2000)  =  04h 06m 36s\n   Dec(J2000) = -71d 55' 28\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows multiple peaks\nwith a duration of about 30 sec.  The peak count rate\nwas ~2100 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 10:05:04.2 UT, 58.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source located at RA, Dec 61.73063, -71.94326 which\nis equivalent to:\n   RA(J2000)  = 04h 06m 55.35s\n   Dec(J2000) = -71d 56' 35.7\"\nwith an uncertainty of 4.0 arcseconds (radius, 90% containment). This\nlocation is 113 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.  We cannot determine whether the source is\nfading at the present time. No spectrum from the promptly downlinked\nevent data is yet available to determine the column density. \n\nThe initial flux in the 2.5 s image was 1.01e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 67 seconds after the BAT trigger. There is a candidate afterglow in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t04:06:55.85 =  61.73272\n  DEC(J2000) = -71:56:34.5  = -71.94293\nwith a 90%-confidence error radius of about 0.62 arc sec. This position is 3.7\narc sec. from the center of the XRT error circle. The estimated magnitude is\n18.39 with a 1-sigma error of about  0.15. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.11. \n\nBurst Advocate for this burst is P.A. Evans (pae9 AT star.le.ac.uk). \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": 20446,
  "createdOn": 1484302542000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 170113A: Swift detection of a burst with an optical counterpart",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 170113A"
}