[vsnet-grb-info 12673] GRB 121202A: TAROT Calern observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14033
SUBJECT: GRB 121202A: TAROT Calern observatory optical observations
DATE:    12/12/02 05:09:10 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz at free.fr>

Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 121202 detected by SWIFT
(trigger 540255) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 34.0s after the GRB trigger
(15.8s after the notice). However, the elevation of the field
increased from 1 degrees above horizon so it was possible
to detect stars on images only 275s after the trigger.

The first image does not show any optical counterpart:
t0+275s to t0+305s : R > 14.9

We co-added series of exposures:
t0+275s to t0+1419s : R > 16.2
t0+1633s to t0+2578s : R > 16.9

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

N.B. Galactic coordinates are lon= 45.1864 lat=+32.8357
and the galactic extinction in R band is about 0.1 magnitude
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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