{
  "bibcode": "2017GCN.22082....1U",
  "body": "T. N. Ukwatta (LANL), D. N. Burrows (PSU), A. D'Ai (INAF-IASFPA),\nV. D'Elia (ASDC), Alex Deich (PSU), J.D. Gropp (PSU),\nJ. A. Kennea (PSU), H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU),\nF. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and\nM. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 15:20:29 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 171102B (trigger=785510).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 288.103, +22.438 which is \n   RA(J2000) = 19h 12m 25s\n   Dec(J2000) = +22d 26' 16\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a multi-peaked\nstructure with a duration of about 20 sec.  The peak count rate\nwas ~1500 counts/sec (15-350 keV), at ~4 sec after the trigger. \n\nThe XRT began observing the field at 15:22:33.3 UT, 123.8 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 288.07776, 22.44512 which is equivalent\nto:\n   RA(J2000)  = 19h 12m 18.66s\n   Dec(J2000) = +22d 26' 42.4\"\nwith an uncertainty of 3.7 arcseconds (radius, 90% containment). This\nlocation is 87 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 4.51\nx 10^21 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 250 seconds with the U filter starting\n124 seconds after the BAT trigger. No credible afterglow candidate has been\nfound in the initial data products. The 2.7'x2.7' sub-image covers none of the\nXRT error circle. The 8'x8' region for the list of sources generated on-board\ncovers 100% of the XRT error circle. The list of sources is typically complete\nto about 18.0 mag. No correction has been made for the expected extinction\ncorresponding to E(B-V) of 0.75. \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": 22082,
  "createdOn": 1509637027000,
  "email": "burrows@astro.psu.edu",
  "subject": "GRB 171102B: Swift detection of a burst",
  "submitter": "David Burrows at PSU/Swift  <burrows@astro.psu.edu>",
  "eventId": "GRB 171102B"
}