TITLE:   GCN CIRCULAR
NUMBER:  23774
SUBJECT: GRB 190123A: GOTO optical limit
DATE:    19/01/23 22:41:39 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <dsteeghs@gmail.com>

D.Steeghs, J.Lyman, K.Ulaczyk (U. Warwick), G.Ramsay (Armagh O.),
M.Dyer (U. Sheffield), A.Obradovic, K. Ackley, D.K. Galloway, E.Rol
(Monash U.), K. Wiersema, B.Gompertz, A.Levan, R.Cutter  (U. Warwick),
V.Dhillon (U. Sheffield), P.O'Brien, R.Starling (U. Leicester),
S.Poshyachinda
(NARIT), D.Pollacco (U. Warwick), E.Thrane (Monash U.), E.Palle (IAC)

report on behalf of the GOTO collaboration:

In response to GRB 190123A (D'Ai et al. GCN Circ. 23769), the
Gravitational-wave Optical Transient Observer (GOTO) observed the
field covering the Swift BAT/XRT positions.

Observations started at 2019-01-23T19:51:53 (7.54 hours post burst)
consisting of a set of 5x120s exposures in our wide L filter
(400-700nm). In line with other reports (Hu et al. GCN 23772;
Lipunov et al. GCN 23770), no optical source g<21.0 is visible
at the updated XRT position (Beardmore et al. GCN 23771),
based on PS1 and SDSS calibrators.

GOTO is operated at the La Palma observing facilities of the
University of Warwick on behalf of a consortium including the
University of Warwick, Monash University, Armagh Observatory, the
University of Leicester, the University of Sheffield, the National
Astronomical Research Institute of Thailand (NARIT) and the Instituto
de Astrofisica de Canarias (IAC) (https://goto-observatory.org/)