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GCN Circular 35733

GRB 240215A: Swift/BAT-GUANO localization of a burst
2024-02-15T21:38:30Z (5 months ago)
Jimmy DeLaunay at Penn State <>
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James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC)  report:

Swift/BAT did not localize GRB 240215A onboard (T0: 2024-02-15T15:33:00.41 UTC, Fermi/GBM trigger 729703985).

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.

In ground analysis of the available TTE data, we find the position of
the burst with SNR 13.9 in the image domain.

At the time of the trigger, Swift did not have a lock on its star tracker so positions may be inaccurate by up to a few tenths of a degree. 

The BAT position is
RA, Dec = 132.237, -6.4058, which is:
    RA (J2000)     08h 48m 56.88s
    Dec (J2000)  -06d 24' 20.88"
with an estimated statistical uncertainty of 3 arcminutes plus ~15 arcminutes due to loss of star tracker loss

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:
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