TITLE:   GCN CIRCULAR
NUMBER:  34159
SUBJECT: GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
DATE:    23/07/07 11:21:40 GMT
FROM:    Aaron Tohuvavohu at University of Toronto <aaron.tohu@gmail.com>

Aaron Tohuvavohu (U Toronto), James DeLaunay (U Alabama), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC)  report:

Swift/BAT did not localize GRB 230707A onboard (T0: 2023-07-07T03:22:51 UTC, Fermi/GBM GCN 34156).

The Fermi 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 ~15 s in duration as seen by BAT.

In ground analysis of the available data, we find the position of the burst with SNR 10.0 in the image domain.
The BAT position is RA, Dec = 171.4759 -21.5125, which is:
    RA (J2000)     11h 25m 54.22s
    Dec (J2000)  -21d 30' 45.0"
with an estimated uncertainty of 2 arcminutes.

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/