[vsnet-grb-info 16207] GRB 150222A: Zadko observatory - Gingin optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17488
SUBJECT: GRB 150222A: Zadko observatory - Gingin optical observations
DATE:    15/02/22 20:32:04 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz at free.fr>

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

We imaged the field of GRB 150222A detected by SWIFT
(trigger 632180) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.

The observations started 55s after the GRB trigger
(42s after the notice). The elevation of the field increased from
51 degrees above horizon and weather conditions
were very good.

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
(Bernardini et al. GCNC 17486) with a limiting magnitude of:
t0+55s to t0+115s : Rlim = 18.5

The second image is 30.0s exposure in tracking mode:
t0+134s to t0+164s : Rlim = 19.8

We co-added a series of exposures:
t0+134s to t0+834s : Rlim = 21.5

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