{
  "body": "K.L. Page and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT\nteam:\n\nThe XRT began observing the field of GRB 250603A (GCN Circ. 40613) at\n01:12:04.7 UT, 101.7 seconds after the BAT trigger. Using\npromptly-collected data (although downlinked after a delay), we find a\nfading, uncatalogued X-ray source with an enhanced position: RA, Dec\n129.93750, -39.29289 which is equivalent to:\n   RA(J2000)  = 08h 39m 45.00s\n   Dec(J2000) = -39d 17' 34.4\"\nwith an uncertainty of 1.9 arcseconds (radius, 90% containment). This\nlocation is 104 arcseconds from the BAT onboard position, within the\nBAT error circle.\n\nGiven the nature of the fading X-ray light-curve, we confirm this trigger\nas GRB 250603A, and not a new Galactic transient.\n\nThis circular is an official product of the Swift-XRT team.\n",
  "eventId": "GRB 250603A",
  "bibcode": "2025GCN.40615....1P",
  "submitter": "K.L. Page at U Leicester <klp5@leicester.ac.uk>",
  "circularId": 40615,
  "submittedHow": "email",
  "subject": "GRB 250603A: Swift-XRT position and confirmation of GRB nature",
  "createdOn": 1748929203214
}