TITLE:   GCN CIRCULAR
NUMBER:  20110
SUBJECT: GRB 161023A: TAROT La Silla observatory optical observations
DATE:    16/10/24 14:52:46 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>

Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:

We imaged the field of GRB 161023A detected by Integral
(trigger 7613, Mereghetti et al., GCN 20103)
with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 64 min after the GRB trigger
(just after the dusk).
The elevation of the field decreased from
71 degrees above horizon and weather conditions
were cloudy so only few images can be measured.

We detected the couterpart mentioned by Gorbovskoy
et al. (GCNC 20102) and Tanvir al. (GCN 20104).

t0 +64 min to t0 +87 min : R    = 15.2 +/-0.2
t0 +96 min to t0+116 min : R    = 15.8 +/-0.4
t0+143 min to t0+149 min : Rlim = 15.8

Magnitudes were estimated with the nearby star
NOMAD-1 0423-1044399 ra=311.0274867 dec=-47.6493169
R=12.37.

Magnitudes are not corrected for galactic dust extinction.