{
  "submittedHow": "web",
  "submitter": "Jimmy DeLaunay at Penn State <delauj2@gmail.com>",
  "bibcode": "2024GCN.35482....1D",
  "circularId": 35482,
  "subject": "GRB 240101C: Swift/BAT-GUANO detection of a short burst",
  "body": "James DeLaunay (PSU), Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:\n\nSwift/BAT did not localize GRB 240101C onboard (T0: 2024-01-01T12:57:23.76 UTC, Fermi GBM Trig 725806648, GRBAlpha GCN 35459, AstroSat CZTI GCN 35478). \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 BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 11.2 in a 0.128 s analysis time bin, starting at T0 s. \n\nNITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 4.2.\n\nSee Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.\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/",
  "eventId": "GRB 240101C",
  "createdOn": 1704421055114
}