[vsnet-grb-info 12814] GRB 130131B: Zadko observatory - Gingin optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14161
SUBJECT: GRB 130131B: Zadko observatory - Gingin optical observations
DATE:    13/01/31 22:37:58 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz at free.fr>

A. Klotz (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA),
B. Gendre (IRAP-CNRS-OMP), M. Boer, K. Siellez, H. Dereli ,
O. Bardho (UNS-CNRS-OCA), A. Williams (PO-UWA), R. Martin (PO-UWA)
report:

We imaged the field of GRB 130131B detected by SWIFT
(trigger 547420) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.

The observations started 70.2s after the GRB trigger
(43.4s after the notice). The elevation of the field decreased from
43 degrees above horizon but gibbous moon was at 23 degrees
away from the GRB position.

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 at the XRT position (Siegel et al.
GCNC 14159) with a limiting magnitude of:
t0+70.2s to t0+130.2s : R > 15.6

The second image is 30.0s exposure in tracking mode:
t0+149s to t0+179s : R > 16.5

An image follow-up continued until 1.5h after the
GRB showing no optical transcient at the limiting
magnitude 16.5. The gibbous moon prevents to obtain
deeper limiting magnitudes.

Magnitudes were estimated with the nearby NOMAD1 stars
and are not corrected for galactic dust extinction.