Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 30393

GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
2021-07-06T18:22:57Z (3 years ago)
Aaron Tohuvavohu at U Toronto <>
Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Jamie A. Kennea
(PSU), Gayathri Raman (PSU) report:

Swift/BAT did not trigger on GRB 210706A (T0: 2021-07-06 08:17:49.9
UTC, Fermi/GBM trigger #  647252274).

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 approximately 10 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 19.

The BAT position is
RA, Dec = 312.0124 +13.3079 deg which is
   RA(J2000)  = 20h 48m 02.98s
   Dec(J2000) =  +13d 18��� 28.4���
with an estimated uncertainty of 5 arcmin.

This position is consistent with the Ferm/GBM localization.

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:
Looking for U.S. government information and services? Visit