GCN Circular 23786
M. Nakamura, T. Sakamoto (AGU) We observed the field of GRB 190123A detected by Swift (D'Ai et al., GCN Circ. 23769) with the 14-inch AGU Robotic Optical Monitor for Astrophysical object - Narrow (AROMA-N) located at the Sagamihara campus of Aoyama Gakuin University. 30 images of 60 sec exposures were taken in the R filter starting from January 23 12:21:49 (UT) about 156 seconds after the trigger and stopped on January 23 12:58:25 (UT). We do not detect the optical afterglow both in the individual images and the stacked image. The estimated five sigma upper limit of the combined image (total exposure of 1800 sec) is ~17.7 mag using the USNO-B1 catalog.