[vsnet-grb-info 4375] GRB 070227: TAROT La Silla observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6159
SUBJECT: GRB 070227: TAROT La Silla observatory optical observations
DATE:    07/02/28 21:51:23 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 070227 detected by SWIFT
(trigger 262347) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 7.76 hours after the GRB trigger
(5.2s after the notice). The elevation of the field decreased
from 41 degrees above horizon, weather conditions
were excellent and the moon elevation was less than 10 degrees.

The date of trigger : t0 = 2007-02-27T22:21:58.752

We co-added a series of 26 long exposures
taken between t0+7.76h and t0+8.98h. The co-added
image has a limiting magnitude R~20.2.
The field is very crowded.

We do not detect any OT in the BAT refined
error box (Barbier et al. GCNC 6158)
nor in the XRT one (Pagani et al. GCNC 6157).
Concerning the XRT error box, we detected clearly
all stars present in the USNO-B1 catalog or in
the DSS-R image.

Magnitudes are not corrected for galactic dust extinction.

N.B. Galactic coordinates are lon=261.2574 lat= -8.2038
and the galactic extinction in R band is 0.7 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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