{
  "submitter": "K.L. Page at U Leicester <klp5@leicester.ac.uk>",
  "subject": "GRB 231214A: Swift detection of a burst",
  "circularId": 35335,
  "eventId": "GRB 231214A",
  "submittedHow": "email",
  "bibcode": "2023GCN.35335....1B",
  "createdOn": 1702586337340,
  "body": "\nR. Brivio (INAF-OAB), P. D'Avanzo (INAF-OAB), S. Dichiara (PSU),\nM. Ferro (INAF-OAB), M. J. Moss (GSFC), K. L. Page (U Leicester),\nD. M. Palmer (LANL), C. Salvaggio (INAF-OAB) and M. A. Williams (PSU)\nreport on behalf of the Neil Gehrels Swift Observatory Team:\n\nAt 20:24:28 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 231214A (trigger=1202386).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 305.736, -72.436 which is \n   RA(J2000) = 20h 22m 57s\n   Dec(J2000) = -72d 26' 09\"\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 30 sec.  The peak count rate\nwas ~8000 counts/sec (15-350 keV), at ~13 sec after the trigger. \n\nThe XRT began observing the field at 20:26:14.5 UT, 106.2 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 305.68573, -72.43256\nwhich is equivalent to:\n   RA(J2000)  = 20h 22m 44.58s\n   Dec(J2000) = -72d 25' 57.2\"\nwith an uncertainty of 1.9 arcseconds (radius, 90% containment). This\nlocation is 56 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 https://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\nUVOT took a finding chart exposure of  39 seconds with the White filter\nstarting 442 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\n0.060. \n\nBurst Advocate for this burst is R. Brivio (riccardo.brivio 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/)\n\n"
}