{
  "bibcode": "2020GCN.27497....1D",
  "body": "James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), and Jamie Kennea\n(PSU) report:\n\nSwift/BAT did not trigger on GRB 200405B (T0: 2020-04-05 03:53:38 UTC).\n\nThe INTEGRAL/SPI-ACS Notice #8579, distributed at T0+35 seconds\ntriggered the Swift Mission Operations Center operated Gamma-ray\nUrgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al.\n2020, in prep).\n\nUpon trigger by these notices, GUANO sent a command to the Swift Burst\nAlert Telescope (BAT) to save 90 seconds of BAT event-mode data from\n[-45,+45] seconds around the time of the burst.\nAll the requested event mode data was delivered to the ground.\n\nIn a ground analysis of the data, we detect the burst in the full\ndetector-summed rates (no localization information) with an SNR of ~9.\nThe detected duration is ~0.5 seconds.\n\nWith a maximum likelihood analysis (DeLaunay et al. 2020, in prep.) on\nthe event-mode data we detect a location for the burst with a square\nroot of the test statistic, sqrt(TS), of 12.4. The sqrt(TS) behaves\nsimilarly to SNR.\nUsing the normal BAT imaging technique, we find an SNR of ~4 at the\nsame location.\n\nThe BAT ground-calculated position is\nRA, Dec = 62.7894, -51.5326 deg which is\n   RA(J2000)  = 4h 11m 9.5s\n   Dec(J2000) =  -51d 31��� 57.4���\nwith an uncertainty of 4 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 11.6%.\n\nDue to the low partial coding, and the lack of any localization\ninformation from SPI-ACS for a consistency check, we stress that while\nthis localization is significant, we cannot be certain of whether or\nnot the burst actually originated from outside the BAT coded field-of-view.\n\nXRT and UVOT follow-up has been triggered and observations of this\nregion have already begun. Results of follow-up observations will be\nreported 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/",
  "circularId": 27497,
  "createdOn": 1586127170000,
  "email": "aaron.tohu@gmail.com",
  "subject": "GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB",
  "submitter": "Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>",
  "eventId": "GRB 200405B"
}