[vsnet-grb-info 4771] GRB 070610: TAROT Calern observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6513
SUBJECT: GRB 070610: TAROT Calern observatory optical observations
DATE:    07/06/12 07:47:02 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz at free.fr>

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

We imaged the field of GRB 070610 detected by SWIFT
(trigger 281993) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 36.1s after the GRB trigger
(7.5s after the notice). The elevation of the field increased from
from 24 degrees above horizon and weather conditions
were good.

The date of trigger : t0 = 2007-06-10T20:52:26.400

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 in the XRT location (Pagani et al.
GCNC 6506) with a limiting magnitude of:
t0+36.1s to t0+96.1s : R > 15.8

The second image is 30.0s exposure in tracking mode:
t0+102.7s to t0+132.7s : R > 16.7

We co-added a series of exposures:
t0+102.7s to t0+387.1s : R > 18.1

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

N.B. Galactic coordinates are lon= 63.2980 lat= -1.0201
and the galactic extinction in R band is 2.5 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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