[vsnet-grb-info 17936] GRB 160504A: TAROT Calern observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19383
SUBJECT: GRB 160504A: TAROT Calern observatory optical observations
DATE:    16/05/04 20:02:56 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz at free.fr>

Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:

We imaged the field of GRB 160504A detected by SWIFT
(trigger 685124) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 57.1s after the GRB trigger
(16.5s after the notice). The elevation of the field increased from
77 degrees above horizon and weather conditions
were good but during twilight.

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 with a limiting magnitude of:
t0+57.1s to t0+117.1s : R > 15.3

The second image is 30.0s exposure in tracking mode:
t0+132.5s to t0+162.5s : R > 15.7

We co-added a series of exposures:
t0+132.5s to t0+426.0s : R > 17.2

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.