{
  "circularId": 39606,
  "body": "P. A. Evans (U Leicester), R. Gupta (NASA GSFC), J. A. Kennea (PSU),\nK. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 16:30:08 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 250306A (trigger=1293340).  Swift did not slew to the burst.\nThe BAT on-board calculated location is \nRA, Dec 354.730, -47.993 which is \n   RA(J2000) = 23h 38m 55s\n   Dec(J2000) = -47d 59' 35\"\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 10 sec.  The peak count rate\nwas ~14,000 counts/sec (15-350 keV), at ~0 sec after the trigger.\n\nDue to a Sun observing constraint, Swift cannot slew to the BAT\nposition until 01:23 UT on 2025 March 18. There will thus be no XRT or\nUVOT data for this trigger before this time.\n\nBurst Advocate for this burst is P. A. Evans (pae9 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",
  "submittedHow": "email",
  "eventId": "GRB 250306A",
  "submitter": "David Palmer at LANL <palmer@lanl.gov>",
  "createdOn": 1741279902056,
  "bibcode": "2025GCN.39606....1E",
  "subject": "GRB 250306A: Swift detection of a burst"
}