[vsnet-grb-info 19909] GRB 171011A: TAROT Calern observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21996
SUBJECT: GRB 171011A: TAROT Calern observatory optical observations
DATE:    17/10/11 21:25:44 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz at free.fr>

Klotz A., Noysena.K., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Eymar, L. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:

We imaged the field of GRB 171011A detected by SWIFT
(trigger 778154) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 41.5s after the GRB trigger
(12.6s after the notice). The elevation of the field
decreased from 7 degrees above horizon and weather
conditions were good.

The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect any OT with a limiting magnitude of:
t0+41.5s to t0+101.5s : Rlim = 16.3

The second image is 30.0s exposure in tracking mode:
t0+114.1s to t0+144.1s : Rlim = 16.6

We co-added a series of exposures:
t0+114.1s to t0+405.3s : Rlim = 17.4

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.