M.Ferro, R. Brivio, P. D'Avanzo, S. Covino, D. Fugazza (INAF-OAB) on behalf of the REM team, report:
We observed the field of GRB 231117A (Laha et al., GCN 35071) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2023 November 17 at 03:04:27 UT (i.e. 68 seconds after the burst) at airmass ~ 3, and lasting for about 2 hours.
From a preliminary analysis, we find no source at the enhanced XRT position (Beardmore et al., GCN 35074) at a mid time of t-t0 = 5.6 min, down to the following 3sigma magnitude upper limits:
r > 18.6
i > 17.9
z > 16.7
(AB; calibrated against the Pan-STARRS catalogue).