{
  "bibcode": "2020GCN.27173....1U",
  "body": "T. N. Ukwatta (LANL), E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA),\nV. D'Elia (SSDC), J. A. Kennea (PSU), N. J. Klingler (PSU),\nS. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC) and\nD. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 03:24:49 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 200224A (trigger=958141).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 248.794, +41.675 which is \n   RA(J2000) = 16h 35m 11s\n   Dec(J2000) = +41d 40' 31\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a complex\nstructure with a duration of about 30 sec.  The peak count rate\nwas ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 03:26:26.9 UT, 97.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 248.7668, 41.6123 which\nis equivalent to:\n   RA(J2000)  = 16h 35m 04.04s\n   Dec(J2000) = +41d 36' 44.1\"\nwith an uncertainty of 2.9 arcseconds (radius, 90% containment). This\nlocation is 237 arcseconds from the BAT onboard position. This position\nmay be improved as more data are received; the latest position is\navailable at https://www.swift.ac.uk/sper.  We cannot determine whether\nthe 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 8.91\nx 10^19 cm^-2 (Willingale et al. 2013). \n\nUVOT results will be reported later. \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/)\n\n[GCN OPS NOTE(24feb20): This is the second Circular in the sequence of 8 circulars\nwhich were all labeled A because of the sequence assigner being offline.  \nThis circular was correctly labelled A.]",
  "circularId": 27173,
  "createdOn": 1582515683000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 200224A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 200224A"
}