[vsnet-grb-info 1931] GRB 050805b: TAROT optical limits

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3770
SUBJECT: GRB 050805b: TAROT optical limits
DATE:    05/08/05 23:44:47 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 050805b detected by SWIFT
(trigger 149131) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

First image was acquired 5.2s after the GCN notice
(55.5s after GRB). The field had an elevation of
63 degrees above horizon and weather conditions were
excellents.

We detected no new source comparing our unfiltered images
with the DSS2-R and 2MASS-K ones and comparing our
succesive frames. From the first frame we give an
early limit:

T(sec since GRB)  Exp(s)  R-mag
   55.5 -  70.5         15  >17.0

Limiting magnitude was estimated with the nearby USNO-B1 stars.

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