{
  "bibcode": "2015GCN.18522....1U",
  "body": "T. N. Ukwatta (LANL), A. D'Ai (INAF-IASFPA), J. A. Kennea (PSU),\nA. Maselli (INAF-IASFPA), P. T. O'Brien (U Leicester) and\nD. M. Palmer (LANL) report on behalf of the Swift Team:\n\nAt 07:49:54 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 151029A (trigger=662086).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 38.529, -35.354, which is\n   RA(J2000)  =  02h 34m 07s\n   Dec(J2000) = -35d 21' 14.4\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  Lightcurve data is not immediately available. \n\nUsing promptly downlinked data we find an uncatalogued X-ray source\nwith an enhanced position: RA, Dec 38.5280, -35.3855 which is\nequivalent to:\n   RA(J2000)  = 02h 34m 06.72s\n   Dec(J2000) = -35d 23' 07.7\"\nwith an uncertainty of 2.3 arcseconds (radius, 90% containment). This\nposition is 113.4 arcsec from the BAT position. This position may be\nimproved as more data are received; the latest position is available at\nhttp://www.swift.ac.uk/sper. \nWe cannot 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 3.41\nx 10^20 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 150 seconds with the White\nfilter  starting 209 seconds after the BAT trigger. The initial\n2.7'x2.7' sub-image does not cover the XRT error circle. There is a candidate\nafterglow in the UVOT srclist at:\nRA(J2000) =   02:34:08.08 = 38.527964\nDEC(J2000) = +35:23:08.8 = -35.385784\nwith a 90%-confidence error radius of about 0.61 arc sec. This position is 1.06\narc sec. from the center of the XRT error circle. The estimated magnitude is\n17.34 with a 1-sigma error of about 0.04. No correction has been made for the\nexpected extinction. \n\nBurst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). \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": 18522,
  "createdOn": 1446108558000,
  "email": "kennea@swift.psu.edu",
  "subject": "GRB 151029A: Swift detection of a burst with an optical counterpart",
  "submitter": "Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>",
  "eventId": "GRB 151029A"
}