TITLE:   GCN CIRCULAR
NUMBER:  31754
SUBJECT: GRB 210722A: TAROT Reunion observatory optical light curve
DATE:    22/03/13 22:11:59 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>

A. Klotz (CNRS-OMP-IRAP),
M. Fortune, R. Augerai (Universite de la Renuion),
P. Thierry  (AGORA),
L. Eymar, S. Antier, M. Boer, A. de Ugarte Postigo (CNRS-OCA-ARTEMIS),

We analyzed archive images of the SWIFT trigger 1061223 (GRB 210722A,
BAT detection by D'Avanzo et al. GCN Circ. 30475,
early optical ground observations by Zhu et al. GCN Circ. 30476,
redshift by Thoene et al. GCN Circ. 30487)
with the TAROT robotic telescope (D=18cm) located
at Les Makes Observatory, Reunion Island, France.

Images were acquired without any filter, camera FLI PL16803
and Takahashi Epsilon 180ED.

According the reference star NOMAD-1 0836-0016935 R=12.57
we give the photometry of the GRB optical transient:

t1(s) t2(s)     R  dmag
  2170  2935 16.08  0.16
  2944  4067 16.24  0.12
  4074  4653 16.78  0.14
  4659  5238 16.60  0.14
  5244  6744 17.04  0.22

t1 and t2 are start and stop acquisition since the trigger.

Magnitudes are not corrected for Galactic dust extinction.