{
  "bibcode": "2018GCN.22909....1S",
  "body": "M. Stamatikos (OSU/NASA/GSFC), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), A. D'Ai (INAF-IASFPA),\nV. D'Elia (ASDC), P. A. Evans (U Leicester), J.D. Gropp (PSU),\nJ. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 08:24:40 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 180706A (trigger=846395).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 181.665, +66.035, which is \n   RA(J2000)  =  12h 06m 40s\n   Dec(J2000) = +66d 02' 05\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows two main peaks\nwith a total duration of about 40 sec.  The peak count rate\nwas ~4000 counts/sec (15-350 keV), at ~28 sec after the trigger. \n\nThe XRT began observing the field at 08:26:08.0 UT, 87.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 181.6428,\n66.0366 which is equivalent to:\n   RA(J2000)  = 12h 06m 34.28s\n   Dec(J2000) = +66d 02' 11.6\"\nwith an uncertainty of 2.4 arcseconds (radius, 90% containment). This\nlocation is 32 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.  We\ncannot determine whether the source is fading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 1.44\nx 10^20 cm^-2 (Willingale et al. 2013). \n\nThe initial flux in the 2.5 s image was 7.91e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 250 seconds with the U filter starting\n307 seconds after the BAT trigger. There is a candidate afterglow in the\nrapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t12:06:34.34 = 181.64308\n  DEC(J2000) = +66:02:13.6  =  66.03712\nwith a 90%-confidence error radius of about 0.77 arc sec. This position is 2.9\narc sec. from the center of the XRT error circle. The estimated magnitude is\n17.74 with a 1-sigma error of about  0.15. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.02. \n\nBurst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 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/too.html.)",
  "circularId": 22909,
  "createdOn": 1530866595000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 180706A: Swift detection of a burst with optical counterpart",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 180706A"
}