[AAVSO-HEN] GRB 071109: TAROT Calern observatory optical observations

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TITLE:   GCN CIRCULAR
NUMBER:  7052
SUBJECT: GRB 071109: TAROT Calern observatory optical observations
DATE:    07/11/10 16:07:00 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 071109 detected by INTEGRAL
(trigger 4761) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 36s after the GRB trigger
(8s after the notice). The elevation of the field decreased from
from 12 degrees above horizon and weather conditions
were good.

We analyzed carefully the following zones:

Mereghetti et al. 2007 (GCNC 7046):
Center 19h19m39.12m +02°02'52.8" radius=2.5 arcmin

Chandra & Frail 2007 (GCNC 7049):
Center 19h19m51.67m +02°01'49.9" radius=15 arcsec

Perri, Stratta et al. 2007 (GCNC 7050):
Center 19h19m53.9m +02°02'47.5" radius=9 arcsec

The first TAROT 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+36s to t0+96s : R > 15.4

The second image is 30.0s exposure in tracking mode:
t0+103s to t0+133s : R > 15.5

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

N.B. Galactic coordinates are lon= 37.9724 lat= -5.3391
and the galactic extinction in R band is about 1.8 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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