GCN Circular 32778
Subject
GRB 221016A: z-band upper limit, possible afterglow brightening
Date
2022-10-17T08:56:18Z (2 years ago)
From
Daniele B Malesani at Radboud U <d.malesani@astro.ru.nl>
D. B. Malesani (Radboud Univ. and DAWN/NBI), D. A. Kann (Goethe Univ.),
L. Izzo (DARK/NBI), S. Covino, P. D'Avanzo (INAF/OAB), N. R. Tanvir
(Univ. Leicester), report on behalf of the Stargate consortium:
We observed the field of GRB 221016A (Page et al., GCN 32774) with the
ESO VLT UT3 (Melipal), using the acquisition camera of the X-shooter
spectrograph. A single 30 s image is available to us, taken on 2022 Oct
17.034 UT (1.17 hr after the trigger). The image seeing was rather poor,
about 2.2".
No source is detected at the position of the optical counterpart
discovered by Strausbaugh & Cucchiara (GCN 32775), down to a 3-sigma
limit z > 20.8 (AB; calibrated against one nearby SkyMapper star).
Comparison between our limit and the magnitudes reported by Strausbaugh
& Cucchiara (GCN 32775) seems to indicate a brightening of the afterglow
between ~1 and ~2 hr after the trigger.
We acknowledge the ESO staff for a quick reaction to our request, in
particular Matias Jones and Felipe Gaete.