[vsnet-grb-info 28222] GRB 210626A: Swift/BAT-GUANO detection and arcminute localization

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30325
SUBJECT: GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
DATE:    21/06/26 15:32:38 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu at gmail.com>

Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Jamie A. Kennea
(PSU), Gayathri Raman (PSU) report:

Swift/BAT did not trigger on GRB 210626A (T0: 2021-06-26 08:16:15.9
UTC, Fermi/GBM GCN 30323).

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 greater than 20 seconds.
The burst occurred during a Swift slew.
Using the normal BAT imaging technique, we find the location for
the GRB with an SNR of 7.6.

The BAT position is
RA, Dec = 221.6199,  -1.1512 deg which is
   RA(J2000)  = 14h 46m 28.78s
   Dec(J2000) =  -1d 09′ 4.3″
with an estimated uncertainty of 5 arcmin.

This position is consistent with the Ferm/GBM localization (GCN 30323).

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/