{
  "bibcode": "2019GCN.26135....1D",
  "body": "A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC),\nJ. A. Kennea (PSU), N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL),\nF. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU)\nreport on behalf of the Neil Gehrels Swift Observatory Team:\n\nAt 21:08:03 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 191101A (trigger=932742).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 251.844, +43.754 which is \n   RA(J2000) = 16h 47m 23s\n   Dec(J2000) = +43d 45' 15\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a complex structure\nwith a duration of about 20 sec.  The peak count rate\nwas ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 21:09:42.4 UT, 99.0 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source located at RA, Dec 251.83474, 43.74103 which\nis equivalent to:\n   RA(J2000)  = 16h 47m 20.34s\n   Dec(J2000) = +43d 44' 27.7\"\nwith an uncertainty of 4.0 arcseconds (radius, 90% containment). This\nlocation is 52 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. No\nspectrum from the promptly downlinked event data is yet available to\ndetermine the column density. \n\nThe initial flux in the 2.5 s image was 8.42e-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 109 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 none of\nthe XRT error circle. The 8'x8' region for the list of sources generated\non-board covers 100% of the XRT error circle. The list of sources is typically\ncomplete to about 18 mag. No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.01. \n\nBurst Advocate for this burst is A. D'Ai (antonino.dai AT inaf.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": 26135,
  "createdOn": 1572644019000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 191101A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 191101A"
}