TITLE:   GCN CIRCULAR
NUMBER:  32091
SUBJECT: GRB 220521A: LCO Optical Detection
DATE:    22/05/22 20:52:33 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>

R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:

We observed GRB 220521A (Dicharia et al., GCN 32076; Fermi GBM Team, GCN 32075) with the LCO 1-m Sinistro instrument at the Teide Observatory, Tenerife site, on May 22, from 00:04 to 00:32 UT (corresponding to 0.73 to 1.20 hours from the GRB trigger time) with the Bessel R and I filters.

We performed a series of 3x300s exposures in R and I bands. We detect an optical counterpart at the NOT optical afterglow location (Malesani et al., 32078 GCN 32078) that is consistent with other optical detections (Malesani et al., GCN 32078; Fynbo et al., GCN 32079; Goranskij et al., GCN 32082). The following magnitudes are calculated using the USNO-B.1 catalog as reference:

R=21.57+/-0.23
I=18.61+/-0.63

These magnitudes are not corrected for galactic extinction.

R.S. is funded by NSF AST grant #1831682