TITLE:   GCN CIRCULAR
NUMBER:  32082
SUBJECT: GRB 220521A: SAO RAS optical observations
DATE:    22/05/22 09:06:22 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

Goranskij V. P. (SAI, Moscow University) and Moskvitin A. S. (Special
Astrophysical Observatory of RAS) report on behalf of a larger
collaboration:

We observed the field of the GRB 220521A (Dichiara et al., GCN 32076;
Evans, GCN 32077) with the SAO RAS 1-m telescope Zeiss-1000
+ CCD-photometer. The observations started 16.6 minutes
after the trigger. We obtained 200 sec. exposures in V, Rc, Ic filters.

The OT (Malesani & Pursimo, GCN 32078; Fynbo et al., GCN 32079)
is clearly detected in Ic and Rc bands (with the brightness of
I = 17.82 +/- 0.04; R = 20.3 +/- 0.2) and not detected in V band
down to the limiting magnitude of V_lim ~ 21.4 (T_mid-T0 = 22.8 min).
Preliminary photometry is based on nearby stars of PS1 catalogue,
gri --> V, R, I by Lupton 2005 transformations.