[vsnet-grb-info 15776] GRB 141031A: TAROT La Silla observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17064
SUBJECT: GRB 141031A: TAROT La Silla observatory optical observations
DATE:    14/11/13 00:15:45 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz at free.fr>

Klotz A., Turpin D. (IRAP-CNRS-OMP),
Boer M., Gendre B., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA),
Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 141031A detected by SWIFT
(trigger 617110) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 45s after the GRB trigger
(15s after the notice). The elevation of the field increased from
45 degrees above horizon and weather conditions
were excellent.

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+45s to t0+105s : Rlim = 14.8

Following images are recorded in tracking mode.
We used late images to substract non variable stars
in the XRT error box.

The second image is 30.0s exposure in tracking mode:
t0+119s to t0+149s : Rlim = 17.5

Later images (until 1800s after the trigger) do not
show any optical afterglow at Rlim = 17.5

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