GCN Circular 29255
Subject
GRB 210104B: Assy optical upper limit
Date
2021-01-05T08:34:20Z (3 years ago)
From
Yerlan Aimuratov at Fesenkov Astrophysical Inst.(FAI) <aimuratov@aphi.kz>
V. Kim (FAI, Pulkovo), I. Reva (FAI), M. Krugov (FAI), Y. Aimuratov
(FAI) report:
We observed the field of GRB 210104B (Laha et al., GCN 29243) with
AZT-20 1.5-m telescope
of Assy-Turgen Observatory (Assy) starting on Jan. 04 (UT) 22:31:15.
We did not find any optical counterpart in our 20x60s stacked image in
the enhanced
XRT position (Evans et al., GCN 29253) down to an upper limit R~23.2
(see also Hu et al., GCN 29249 and Fu et al., GCN 29250).
Preliminary photometry of the filed is the following:
Date UT start t-T0 Filter Exp. OT Err.
UL(3-sigma) FWHM
(mid, days) (s)
(")
2021-01-04 22:31:15 0.06325 r' 20*60 n/d n/d 23.2
2.3
Further observations on this object are not planned except personal
request.