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.