[vsnet-grb-info 15991] GRB 150103A: Zadko observatory - Gingin optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17273
SUBJECT: GRB 150103A: Zadko observatory - Gingin optical observations
DATE:    15/01/04 00:47:23 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 150103A detected by SWIFT
(trigger 623368) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.

The observations started 121.6s after the GRB trigger
(44.7s after the notice). The elevation of the field decreased
from 62 degrees above horizon and weather conditions
were good but during the dawn.

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 in the XRT error box provided by
Osborne et al. (GCNC 17272) with a limiting magnitude of:

t0+121.6s to t0+181.6s : Rlim = 16.7

The second image is 30.0s exposure in tracking mode:

t0+200.0s to t0+230.0s : Rlim = 18.9

The following images give the same limits:
t0+239s to t0+347s : Rlim = 18.9

Images taken later are saturated due to the dawn.

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