{
  "circularId": 38547,
  "body": "R. Gupta (NASA GSFC), C. Gronwall (PSU), K. L. Page (U Leicester) and\nT. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 02:19:00 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 241213A (trigger=1274039).  Swift slewed immediately to the burst.\nThe BAT on-board calculated location is \nRA, Dec 116.148, +35.280 which is \n   RA(J2000) = 07h 44m 35s\n   Dec(J2000) = +35d 16' 49\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a bright peak \nwith a duration of about 15 sec.  The peak count rate\nwas ~9500 counts/sec (15-350 keV), at ~0 sec after the trigger.\n\nThe XRT began observing the field at 02:25:36.0 UT, 395.9 seconds after\nthe BAT trigger. Using promptly downlinked data we find a fading,\nuncatalogued X-ray source with an enhanced position: RA, Dec 116.17145,\n35.27944 which is equivalent to:\n   RA(J2000)  = 07h 44m 41.15s\n   Dec(J2000) = +35d 16' 46.0\"\nwith an uncertainty of 1.9 arcseconds (radius, 90% containment). This\nlocation is 68 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. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (6.66 x\n10^20 cm^-2, Willingale et al. 2013), with an excess column of 5\n(+2.07/-1.84) x 10^21 cm^-2 (90% confidence).\n\nUVOT took a finding chart exposure of 250 seconds with the U filter starting\n318 seconds after the BAT trigger. No credible afterglow candidate has been\nfound in the initial data products. The 2.7'x2.7' sub-image covers none of the\nXRT error circle. The 8'x8' region for the list of sources generated on-board\ncovers 100% of the XRT error circle. The list of sources is typically complete\nto about 18.0 mag. No correction has been made for the expected extinction\ncorresponding to E(B-V) of 0.060.\n\nBurst Advocate for this burst is R. Gupta (rahulbhu.c157 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",
  "eventId": "GRB 241213A",
  "submitter": "K.L. Page at U Leicester <klp5@leicester.ac.uk>",
  "subject": "GRB 241213A: Swift detection of a burst",
  "bibcode": "2024GCN.38547....1G",
  "createdOn": 1734057587165,
  "submittedHow": "email"
}