TITLE:   GCN CIRCULAR
NUMBER:  6783
SUBJECT: GRB 070913: TAROT La Silla observatory optical observations
DATE:    07/09/13 01:23:01 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>

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

We imaged the field of GRB 070913 detected by SWIFT
(trigger 290843) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 87.3s after the GRB trigger
(69.4s after the notice). The elevation of the field decreased from
from 35 degrees above horizon and weather conditions
were good.

The date of trigger : t0 = 2007-09-13T00:36:44.064

The first image is 30.0s exposure in tracking mode.
We do not detect any OT with a limiting magnitude of:
t0+87.3s to t0+117.3s : R > 17.8

We co-added a series of exposures:
t0+123.6s to t0+576.5s : R > 18.4

Further observations are in progress.

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

N.B. Galactic coordinates are lon=340.2109 lat=+27.9232
and the galactic extinction in R band is 0.4 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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