[vsnet-grb-info 12593] GRB 121108A: TAROT Calern observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13953
SUBJECT: GRB 121108A: TAROT Calern observatory optical observations
DATE:    12/11/08 18:12:31 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz at free.fr>

Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 121108A detected by SWIFT
(trigger 537921) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 33.8s after the GRB trigger
(19.2s after the notice). The elevation of the field increased from
20 degrees above horizon and weather conditions
were good for the first images and became cloudy.

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+33.8s to t0+93.8s : R > 15.8

The second image is 90.0s exposure in tracking mode:
t0+417.6s to t0+507.6s : R > 16.5

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

N.B. Galactic coordinates are lon=156.8411 lat=+11.3702
and the galactic extinction in R band is about 1.0 magnitude
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.