[vsnet-grb-info 4742] GRB 070411: TAROT Calern observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6487
SUBJECT: GRB 070411: TAROT Calern observatory optical observations
DATE:    07/06/08 05:50:21 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz at free.fr>

Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:

We imaged the field of GRB 070411 detected by SWIFT
(trigger 275087) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
Analysis of this burst is late due to a technichal
problem.

The observations started 45.6s after the GRB trigger
(5.7s after the notice) when the burst was still active.
The elevation of the field decreased from
from 33 degrees above horizon and weather conditions
were poor (cloudy).

The date of trigger : t0 = 2007-04-11T20:12:33.120

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 the UVOT candidate position (Moretti
et al., GCN 6267) with a limiting magnitude of:
t0+45.6s to t0+105.6s : R > 14.6

The second image is 30.0s exposure in tracking mode:
t0+112.6s to t0+142.6s : R > 15.5

Further images have no significant higher limiting
magnitude.

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

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