GCN Circular 30916

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/