[vsnet-grb-info 27077] GRB 201223A: AROMA-N Optical Observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29180
SUBJECT: GRB 201223A: AROMA-N Optical Observation
DATE:    20/12/27 22:15:11 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

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.