{
  "bibcode": "2023GCN.33499....1R",
  "body": "Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU),\nJames DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto) report:\n\nSwift/BAT did not localize GRB 230320B onboard (T0:\n2023-03-20T21:12:25 UTC, Fermi/GBM trig 701039550, CALET trig\n1363381768, GECAM trig 163, AstroSat/CZTI GCN 33492).\n\nThe Fermi, CALET and GECAM notices, distributed in near real-time,\ntriggered the Swift Mission Operations Center operated Gamma-ray\nUrgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al.\n2020, ApJ, 900, 1).\n\nUpon trigger by this notice, GUANO sent a command to the Swift Burst\nAlert Telescope (BAT) to save 200 seconds of BAT event-mode data from\n[-50,+150] seconds around the time of the burst. All the requested\nevent mode data was delivered to the ground.\n\nThe BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ,\n941, 169), detects the burst with a sqrt(TS) of 12.04 in a 4.096 s\nanalysis time bin.\nThe Fermi/GBM localization is consistent with being outside the BAT FOV.\n\nSee Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief\ndescriptions and interpretation of sqrt(TS), DeltaLLHPeak, and\nDeltaLLHOut.\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/",
  "circularId": 33499,
  "createdOn": 1679442233000,
  "email": "aaron.tohu@gmail.com",
  "subject": "GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV",
  "submitter": "Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>",
  "eventId": "GRB 230320B"
}