TITLE: GCN CIRCULAR NUMBER: 12595 SUBJECT: GRB 111123A, GROND observations DATE: 11/11/24 16:04:07 GMT FROM: Ana Nicuesa at TLS Tautenburg A. Rossi, A. Nicuesa Guelbenzu, S. Klose (all Tautenburg), P. Afonso (American River College), and J. Greiner (MPE) report on behalf of the GROND team: We observed the field of GRB 111123A (Stamatikos, GCN 12587) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2-m MPI/ESO telescope on La Silla. Observations started at 6:30 UT on November 24, about 12 hr after the burst, and continued for about 1.5 hr. They were performed at an average seeing of 1 arcsec and an average airmass of 1.5. We do not detect the source discovered by Xu et al. (GCN 12589; see also Fugazza et al. GCN 12593). At a mean time of November 24, 7:10 UT, we measure the following preliminary upper limits (AB magnitudes): g' > 24.5, r' > 24.6, i' > 23.7, J > 21.2, H > 20.9, K > 19.9. The data are calibrated against GROND zeropoints and 2MASS field stars.