GCN Circular 8998

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

We imaged the field of GRB 090313 detected by Swift
(trigger 346386) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 104s after the GRB trigger
The elevation of the field decreased from
37 degrees above horizon and weather conditions
were good but the moon was at 20 deg.

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 OT reported by Chornock et al. (GCNC 8979)
with a limiting magnitude of:
t0+104s to t0+164s : R > 15.3

The second image is 30.0s exposure in tracking mode:
t0+186s to t0+216s : R > 16.6

We co-added a series of exposures.
The OT is detected:
t0+186s to t0+421s : R = 17.1

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

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