{
  "subject": "SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare",
  "bibcode": "2023GCN.35022....1T",
  "circularId": 35022,
  "body": "Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Samuele Ronchini (PSU)  report:\n\nSwift/BAT did not localize SGRJ1555-5402 onboard (T0: 2023-11-11T21:35:11.4 UTC, Fermi trigger n. 721431316).\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), detects the burst in a 0.128 s analysis time bin with a sqrt(TS) of 29.2, starting at T0 - 0.128 s. \nAn arcminute localization is found with DeltaLLHOut of 86.12 and a DeltaLLHPeak of 112.11.\n\nFrom the spectral template, the best fit value of the peak energy is 77.6 keV.\n\nSee Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.\n\nThe BAT position is\nRA, Dec = 238.818, -54.077 deg which is\n   RA(J2000)  =  15h 55m 16.32s\n   Dec(J2000) = -54d 04m 37.20s\nwith an estimated uncertainty of 5 arcmin radius.\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/",
  "submittedHow": "web",
  "submitter": "Samuele Ronchini at PSU <sjs8171@psu.edu>",
  "createdOn": 1699932554443
}