[vsnet-grb-info 14641] GRB 140311B: TAROT Calern observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15955
SUBJECT: GRB 140311B: TAROT Calern observatory optical observations
DATE:    14/03/12 00:42:49 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz at free.fr>

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

We imaged the field of GRB 140311B detected by SWIFT
(trigger 513505) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 5 minutes after the GRB trigger
The elevation of the field increased from
20 degrees above horizon and weather conditions
were good.

The first image is 60.0s exposure in tracking mode.
We do not detect the OT discovered by Xu et al.
(GCNC 15949) with a limiting magnitude of:
t0+246s to t0+306s : Rlim = 17.3

We co-added a series of exposures:
We do not detect the OT with limiting magnitudes of:
t0+246s to t0+511s : Rlim = 17.8
t0+541s to t0+1568s : Rlim = 18.4

Magnitudes were estimated with the nearby NOMAD1 stars
and are not corrected for galactic dust extinction.

N.B. Galactic coordinates are lon= 80.3934 lat=+39.5637
and the galactic extinction in R band is about 0.2 magnitude
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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