[vsnet-grb-info 11914] GRB 120521A: TAROT La Silla observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13303
SUBJECT: GRB 120521A: TAROT La Silla observatory optical observations
DATE:    12/05/21 06:34:10 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz at free.fr>

Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 120521A detected by SWIFT
(trigger 522578) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 35.2s after the GRB trigger
(15.1s after the notice). The elevation of the field decreased from
10 degrees above horizon and weather conditions
were 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 in the XRT position (Chester et al.
GCNC 13302) with a limiting magnitude of:
t0+35.2s to t0+95.2s : R > 15.8

The second image is 30.0s exposure in tracking mode:
t0+108.9s to t0+138.9s : R > 16.5

We co-added a series of exposures:
t0+109s to t0+533s : R > 17.4

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