{
  "submittedHow": "email",
  "body": "\nK. L. Page (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU),\nD. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII) and\nM. A. Williams (PSU) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 21:29:04 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 231210B (trigger=1201696).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 95.772, -48.359 which is \n   RA(J2000) = 06h 23m 05s\n   Dec(J2000) = -48d 21' 32\"\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 15 sec.  However, since this\nGRB occurred while the spacecraft was leaving the SAA, the rate\nlightcurve is hard to interpret.  The peak count rate\nwas ~1500 counts/sec (15-350 keV), at ~T+0 sec after the trigger. \n\nThe XRT began observing the field at 21:31:07.8 UT, 123.4 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 95.79386,\n-48.37201 which is equivalent to:\n   RA(J2000)  = 06h 23m 10.53s\n   Dec(J2000) = -48d 22' 19.2\"\nwith an uncertainty of 1.9 arcseconds (radius, 90% containment). This\nlocation is 70 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. 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 4.31e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 462 seconds after the BAT trigger. Due to tracking issues, the \nUVOT image is blurred. However, comparison with DSS shows that there appears\nto be a new source coincident with the XRT localization. Further data and \nanalysis will be needed to report an accurate localization and magnitude \nof this object. \n\nBurst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). \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",
  "subject": "GRB 231210B: Swift detection of a burst with optical counterpart",
  "createdOn": 1702244987651,
  "eventId": "GRB 231210B",
  "circularId": 35314,
  "submitter": "Jamie Kennea at Penn State <jak51@psu.edu>",
  "bibcode": "2023GCN.35314....1P"
}