TITLE:   GCN CIRCULAR
NUMBER:  32078
SUBJECT: GRB 220521A: NOT optical afterglow detection
DATE:    22/05/22 00:09:27 GMT
FROM:    Daniele B Malesani at Radboud U  <d.malesani@astro.ru.nl>

D. B. Malesani (Radboud Univ. and DAWN/NBI) and T. Pursimo (NOT) report 
on behalf of more people:

We observed the field of GRB 220521A (Dichiara et al., GCN 32076) with 
the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. In a 
300-s exposure beginning on 2022 May 21.983 UT (0.248 hr after the GRB), 
we detect a new object consistent with the UVOT-enhanced X-ray position 
(Evans, GCN 32077), at J2000 coordinates:

RA = 18:20:55.13
Dec = +10:22:20.5

Calibration is against the Gaia catalog, with an expected uncertainty < 
0.3".

Photometry against nearby Pan-STARRS calibrators yields r = 21.06 +- 
0.03 AB. Given the consistency with the X-ray position and the lack of 
detection in the Pan-STARRS archival images, we conclude that this 
source is the optical afterglow of GRB 220521A.