GCN Circular 29180
M. Nakamura, K. Hasuda, T. Sakamoto (AGU) We observed the field of GRB 201223A detected by Swift (Gropp et al., GCN Circ. 29158) with the 14-inch AGU Robotic Optical Monitor for Astrophysical object - Narrow (AROMA-N) located at the Sagamihara campus of Aoyama Gakuin University. 58 images of 60 sec exposures were taken in the R filter starting from December 23 18:04:02 (UT) about 5.6 minutes after the trigger and stopped on December 23 19:16:09 (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 3480 sec) is ~17.3 mag using the USNO-B1 catalog.