[vsnet-grb-info 20207] GRB 180102A AROMA-N optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22303
SUBJECT: GRB 180102A AROMA-N optical observation
DATE:    18/01/06 00:57:23 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

Y. Kitaoka, T. Sakamoto (AGU)

We observed the field of GRB 180102A detected by Swift
(Page et al. GCN circ. 22292) with the 0.3 m AROMA-N telescope
located at Aoyama Gakuin University (Sagamihara, Japan).

10 images of 60 sec exposures were taken in the R filter starting
from January 2 on 15:52:26 (UT) about 3 minutes after the trigger
and stopped on 16:04:28 (UT).  We do not detect the optical afterglow
both in the individual images and the stacked image at the location of
the X-ray afterglow (Beardmore et al. GCN circ. 22294).  The estimated
five sigma upper limit is ~16.0 mag using the USNO-B1 catalog.