{
  "createdOn": 1749691671693,
  "subject": "GRB 250612A: Swift detection of a burst or new Galactic transient Swift J1643.6-3854",
  "body": "M. H. Siegel (PSU), J. J. DeLaunay (PSU), R. Gupta (NASA GSFC) and\nM. A. Williams (PSU) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 01:02:05.82 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 250612A (trigger=1323295). The BAT on-board calculated location is RA, Dec 250.903, -38.902 which is \n   RA(J2000) = 16h 43m 37s\n   Dec(J2000) = -38d 54’ 06\"\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 5 sec.  The peak count rate\nwas ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger.\n\nDue to a Moon observing constraint, Swift cannot slew to the BAT\nposition until 11:59 UT on 2025 June 12. There will thus be no XRT or\nUVOT data for this trigger before this time.\n\nGiven the location of the BAT detection at a Galactic latitude of 4.6 deg and no confirmation of a fading afterglow due to observing constraints, we cannot rule out a Galactic origin. \nIf this is a new Galactic transient we would name it Swift J1643.6-3854.\n\nBurst Advocate for this burst is M. H. Siegel (siegel AT swift.psu.edu).\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",
  "bibcode": "2025GCN.40694....1S",
  "eventId": "GRB 250612A",
  "submittedHow": "email",
  "circularId": 40694,
  "submitter": "James DeLaunay at PSU <jjd330@psu.edu>"
}