TITLE:   GCN CIRCULAR
NUMBER:  31753
SUBJECT: GRB 210222B: TAROT Reunion observatory optical light curve
DATE:    22/03/13 22:11:11 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 1034325 (GRB 210222B,
BAT detection by Gropp et al. GCN Circ. 29545,
early optical ground observations by Fernandez-Garcia et al. GCN Circ. 
29546,
redshift by Agui Fernandez et al. GCN Circ. 29552)
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 0750-0237314 R=15.43
we give the photometry of the GRB optical transient:

t1(s) t2(s)     R  dmag
   342   433 15.76  0.06
   439   529 16.08  0.07
   536   626 16.14  0.08
   658   748 16.28  0.09
   755   845 16.38  0.09
   853   942 16.38  0.09
  1526  1706 16.98  0.12
  1714  1894 17.28  0.15
  1902  2543 17.32  0.13
  2550  3317 17.74  0.21
  3347  4843 17.92  0.25
  4852  6755 18.52  0.47

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

Magnitudes are not corrected for Galactic dust extinction.