TITLE:   GCN CIRCULAR
NUMBER:  29059
SUBJECT: GRB 201216A: Swift/BAT-GUANO detection and arcminute localization
DATE:    20/12/16 22:05:10 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU),  Jamie Kennea (PSU) report:

Swift/BAT did not trigger on GRB 201216A (T0: 2020-12-16 19:00:31 UTC,
Fermi/GBM TRIGGER 629838036, GCN 29057).

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.

Using the normal BAT imaging technique, we find the location of the
GRB with an SNR of 8.9.
The BAT position is
RA, Dec = 201.4872, +36.3116 deg which is
   RA(J2000)  = 13h 25m 56.93s
   Dec(J2000) =  +36d 18' 41.76"
with an estimated uncertainty of 3 arcmin.

This position is consistent with the Fermi GBM localization (GCN 29057).

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/