GCN Circular 28971
Subject
GRB 201128B: Swift/BAT-GUANO detection and arcminute localization
Date
2020-11-30T23:46:57Z (4 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Jamie Kennea (PSU) report:
Swift/BAT did not trigger on GRB 201128B (T0: 2020-11-28 17:54:11 UTC,
Fermi/GBM TRIGGER 628278856).
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 burst is detected in BAT with a duration of ~15 seconds. This was
a weak and slow burst that occurred during a rapid part of a Swift
slew. The position of the burst was found with a novel and
uncalibrated slew image mosaicing procedure, and so the positional
uncertainty is not yet well characterized.
The BAT position is
RA, Dec = 339.354, -49.246 deg which is
RA(J2000) = 22h 37m 24.96s
Dec(J2000) = -49d 14��� 45.6���
with an estimated uncertainty of at least 5 arcmin.
This position is consistent with the Fermi GBM localization
(https://gcn.gsfc.nasa.gov/other/628278856.fermi).
XRT and UVOT follow-up has been requested. Results of follow-up
observations will be reported in future circulars.
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/