GCN Circular 30916
Subject
SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
Date
2021-10-01T18:01:34Z (4 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Gayathri Raman
(PSU), Jamie A. Kennea (PSU) report:
Swift/BAT did not localize SGR 1935+2154 (T0: 2021-10-01 00:04:04.3
UTC, Fermi/GBM trigger # 654739449) onboard.
The Fermi/GBM 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).
Upon 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.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu, in prep),
detects a burst and localizes it to the position of SGR 1935+2154.
The burst is detected in BAT with a duration of less than 64 ms.
This position is consistent with the Ferm/GBM localization.
GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/