[vsnet-grb-info 27151] GRB 210104A: DOAO optical afterglow observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29254
SUBJECT: GRB 210104A: DOAO optical afterglow observations
DATE:    21/01/05 03:31:37 GMT
FROM:    Gregory SungHak Paek at SNU  <shpaek at astro.snu.ac.kr>

Gregory S.H. Paek (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Taewoo Kim,
and Wonseok Kang (DOAO) on behalf of a larger collaboration

We observed the optical counterpart of GRB 210104A (E. Troja et al.,
GCN #29233)
with the 1-m class telescope in Deokheung Optical Astronomy Observatory
(DOAO). We calibrated flux with the SDSS catalog and used an AB magnitude
system.
----------------------------------------------------------
Filter Date-obs[UT]            Exp.time[s] Mag   Mag Error
----------------------------------------------------------
R      2021-01-04T13:37:29.100 300*4       18.34  0.07
I      2021-01-04T13:42:37.050 300*4       18.04  0.05
----------------------------------------------------------
The magnitudes are not corrected for galactic extinction.