GCN Circular 19755

A. Moskvitin (SAO RAS) and I. Soloviev  (Saint-Petersburg Univ.),
report on behalf of the larger GRB follow-up team.

We observed the field of GRB 160801A (D'Elia et al., GCNC#19744)
with Zeiss-1000 - the 1-meter telescope of Special Astrophysical
Observatory of Russian Academy of Sciences on August 1, 2016,
(18:14:58--20:09:29 UT), T_mid - T0 = 9.73 hours. We have obtained
18 x 300 sec. images in the Rc band under good weather conditions.
Within the XRT error circle (Goad et al., GCNC#19746)
we did not detect any new objects down to the limiting magnitude
R_lim = 23.2.

When inspecting SDSS images we found a faint stellar-like source
J141103.21+132921.4 located near the enhanced XRT error circle.
The recalculated magnitude of the object from SDSS images
(Epoch = 2003.41) should be R = 20.94 +/- 0.05 (based on the
Lupton 2005 equations).

In our stacked frame at the edge of the XRT error circle
(the offset 2".2) we detected the same source with a brightness of
R = 20.9 +/- 0.1. Therefore, we can not detect significant differences
between two epochs. This result is in agreement with info reported
by Cano et al. (GCNC#19753). Our preliminary photometry is based
on the nearby SDSS stars, which magnitudes are converted to the
Johnson-Cousins system with the same Lupton 2005 equations.

The finding chart based on Zeiss-1000 observations can be found at
ftp://ftp.sao.ru/pub/grb/GRB160801A/GRB160801A_z1000.jpg

We are grateful to technical staff of SAO RAS for assistance in
observations.

<ftp://ftp.sao.ru/pub/grb/GRB160801A/GRB160801A_z1000.jpg>