{
  "body": "James DeLaunay (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (Caltech), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC)  report:\n\nSwift/BAT did not localize GRB 250601A onboard (T0: 2025-06-01T17:29:35.54 UTC, Fermi GCN 40596).\n\nThe Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). \n\nUpon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.\n\nThe position is found with standard imaging, with an SNR = 8.7. The duration of the burst is ~1 sec.\n\nThe BAT position is\n\nRA, Dec = 90.0709, -57.2892 deg which is\n\n   RA(J2000)  = 06h 00m 17.02s\n   \n   Dec(J2000) = -57d 17’ 21.1″\n   \nwith an estimated uncertainty of 3 arcmin radius.\n\nMore details about this burst can be found on the trigger report page here:\nhttps://guano.swift.psu.edu/trigger_report?id=770491811\n\nXRT and UVOT follow-up has been requested.\nResults of follow-up observations will be reported in future circulars.\n\nGUANO is a fully autonomous, extremely low latency, spacecraft\ncommanding pipeline designed for targeted recovery of BAT event mode\ndata around the times of compelling astrophysical events to enable\nmore sensitive GRB searches.\n\nA live reporting of Swift/BAT event data recovered by GUANO can be\nfound at: https://www.swift.psu.edu/guano/",
  "createdOn": 1748816502161,
  "circularId": 40600,
  "submittedHow": "web",
  "submitter": "Samuele Ronchini at PSU <sjs8171@psu.edu>",
  "bibcode": "2025GCN.40600....1D",
  "eventId": "GRB 250601A",
  "format": "text/markdown",
  "subject": "GRB 250601A: Swift/BAT-GUANO arcminute localization of a likely short burst"
}