{
  "bibcode": "2022GCN.32827....1B",
  "body": "R. Brivio (INAF-OAB), P. D'Avanzo (INAF-OAB), M. Ferro (INAF-OAB),\nJ.D. Gropp (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),\nS. Laha (GSFC/UMBC), F. E. Marshall (NASA/GSFC),\nK. L. Page (U Leicester), D. M. Palmer (LANL),\nT. M. Parsotan (GSFC/UMBC/CRESSTII), T. Sbarrato (INAF-OAB),\nB. Sbarufatti (INAF-OAB), M. H. Siegel (PSU) and M. A. Williams (PSU)\nreport on behalf of the Neil Gehrels Swift Observatory Team:\n\nAt 13:00:27 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 221024A (trigger=1131029).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 169.718, +33.041 which is \n   RA(J2000) = 11h 18m 52s\n   Dec(J2000) = +33d 02' 28\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single-peaked\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 13:02:36.5 UT, 129.5 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 169.74060, 33.04207 which is equivalent\nto:\n   RA(J2000)  = 11h 18m 57.74s\n   Dec(J2000) = +33d 02' 31.5\"\nwith an uncertainty of 3.5 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 (2.86 x\n10^20 cm^-2, Willingale et al. 2013), with an excess column of 4\n(+2.22/-1.98) x 10^21 cm^-2 (90% confidence). \n\nUVOT took a finding chart exposure of 250 seconds with the UVW2 filter\nstarting  127 seconds after the BAT trigger. No credible afterglow\ncandidate has been  found in the initial data products. The 2.7'x2.7'\nsub-image processing failed because there is no aspect solution due\nto a nearby very bright star.   Results from the list of  sources\ngenerated on-board are not available at this time. \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/)",
  "circularId": 32827,
  "createdOn": 1666617802000,
  "email": "jak51@psu.edu",
  "subject": "GRB 221024A: Swift detection of a burst",
  "submitter": "Jamie Kennea at Penn State U  <jak51@psu.edu>",
  "eventId": "GRB 221024A"
}