{
  "bibcode": "2019GCN.26112....1D",
  "body": "V. D'Elia (SSDC), E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA),\nJ.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU),\nH. A. Krimm (NSF), D. M. Palmer (LANL) and A. Tohuvavohu (U Toronto)\nreport on behalf of the Neil Gehrels Swift Observatory Team:\n\nAt 21:23:31 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 191031D (trigger=932608).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 283.275, +47.639 which is \n   RA(J2000) = 18h 53m 06s\n   Dec(J2000) = +47d 38' 19\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single peak\nstructure with a duration of about 0.4 sec.  The peak count rate\nwas ~18000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 21:24:59.8 UT, 88.8 seconds after\nthe BAT trigger. Using promptly downlinked data we find a fading,\nuncatalogued X-ray source with an enhanced position: RA, Dec 283.2890,\n47.6438 which is equivalent to:\n   RA(J2000)  = 18h 53m 09.37s\n   Dec(J2000) = +47d 38' 37.7\"\nwith an uncertainty of 2.3 arcseconds (radius, 90% containment). This\nlocation is 38 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\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 92 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 100% of\nthe XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nXRT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.08. \n\nThis GRB was also detected by Fermi/GBM (trignum=191031891, GCN\n26111), and the INTEGRAL/SPIACS event (trignum=8402). We note that the\nFermi automated circular has misnamed this event GRB 191031C. \n\nBurst Advocate for this burst is V. D'Elia (delia AT ssdc.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/)",
  "circularId": 26112,
  "createdOn": 1572558821000,
  "email": "hkrimm@nsf.gov",
  "subject": "GRB 191031D: Swift detection of a short hard burst",
  "submitter": "Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>",
  "eventId": "GRB 191031D"
}