{
  "bibcode": "2014GCN.16878....1D",
  "body": "V. D'Elia (ASDC), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC),\nL. Izzo (URoma/ICRA), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),\nD. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf\nof the Swift Team:\n\nAt 23:20:54 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 141004A (trigger=614390).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 76.730, +12.833 which is \n   RA(J2000)  =  05h 06m 55s\n   Dec(J2000) = +12d 49' 59\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single FRED\nstructure with a duration of about 8 sec.  The peak count rate\nwas ~17000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 23:21:54.2 UT, 59.9 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 76.73435, 12.81935 which is equivalent\nto:\n   RA(J2000)  = 05h 06m 56.24s\n   Dec(J2000) = +12d 49' 09.7\"\nwith an uncertainty of 4.3 arcseconds (radius, 90% containment). This\nlocation is 51 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 in excess of the Galactic value (3.14 x\n10^21 cm^-2, Willingale et al. 2013), with an excess column of 5.3\n(+5.50/-4.31) x 10^21 cm^-2 (90% confidence). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 64 seconds after the BAT trigger. There is a candidate afterglow in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t05:06:56.14 =  76.73391\n  DEC(J2000) = +12:49:11.3  =  12.81981\nwith a 90%-confidence error radius of about 0.61 arc sec. This position is 2.3\narc sec. from the center of the XRT error circle. The estimated magnitude is\n17.39 with a 1-sigma error of about  0.14. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.32. \n\nBurst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). \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": 16878,
  "createdOn": 1412465388000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 141004A: Swift detection of a burst with an optical counterpart",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 141004A"
}