{
  "bibcode": "2017GCN.20603....1T",
  "body": "E. Troja (NASA/GSFC/UMCP), D. N. Burrows (PSU),\nA. Cholden-Brown (PSU), H. A. Krimm (CRESST/NSF/USRA),\nA. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC) and\nK. L. Page (U Leicester) report on behalf of the Swift Team:\n\nAt 12:39:09 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 170205A (trigger=736843).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 262.151, -0.053 which is \n   RA(J2000) = 17h 28m 36s\n   Dec(J2000) = -00d 03' 08\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a double-peaked\nstructure with a duration of about 25 sec.  The peak count rate\nwas ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 12:40:10.9 UT, 61.1 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source with an enhanced position: RA, Dec\n262.1696, -0.0626 which is equivalent to:\n   RA(J2000)  = 17h 28m 40.70s\n   Dec(J2000) = -00d 03' 45.3\"\nwith an uncertainty of 2.2 arcseconds (radius, 90% containment). This\nlocation is 75 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. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (1.97 x\n10^21 cm^-2, Willingale et al. 2013), with an excess column of 6.4\n(+5.93/-4.46) x 10^21 cm^-2 (90% confidence). \n\nThe initial flux in the 2.5 s image was 7.05e-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 314 seconds after the BAT trigger. There is a candidate afterglow in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t17:28:40.69 = 262.16953\n  DEC(J2000) = -00:03:47.3  =  -0.06313\nwith a 90%-confidence error radius of about 0.62 arc sec. This position is 1.9\narc sec. from the center of the XRT error circle. The estimated magnitude is\n17.62 with a 1-sigma error of about  0.14. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.35. \n\nBurst Advocate for this burst is E. Troja (eleonora.troja 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": 20603,
  "createdOn": 1486299520000,
  "email": "burrows@astro.psu.edu",
  "subject": "GRB 170205A: Swift detection of a burst with an optical counterpart",
  "submitter": "David Burrows at PSU/Swift  <burrows@astro.psu.edu>",
  "eventId": "GRB 170205A"
}