TITLE:   GCN CIRCULAR
NUMBER:  32535
SUBJECT: GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
DATE:    22/09/08 16:56:10 GMT
FROM:    Charles Kilpatrick at Northwestern U  <ckilpatrick@northwestern.edu>

A. C. Gordon (Northwestern U.), N. Tejos (PUCV), and C. D. Kilpatrick (Northwestern U.) report on behalf of the F4 Collaboration:

"We observed the Swift/BAT-GUANO localization of GRB 220831A (Tohuvavohu et al., GCN #32506) with Gemini South/GMOS in follow-up to the DECam observation (Freeburn et al., GCN #32516). Imaging in r- and i-band were carried out starting at UT 2022-09-05 04:05:49.

We detect the source in i-band and an upper limit in r-band at the following position (coincident with GCN #32516) at the coordinates (J2000):

RA = 01:37:00.9864
Dec = -41:35:34.296

From this source, we measure magnitudes (AB mag):
r > 26.4
i = 25.69 +/- 0.31

Our observations confirm that the source presented in GCN #32516 has faded significantly, which supports the hypothesis that it was a transient source associated with GRB 220831A and its weak X-ray counterpart (Dichiara et al., GCN #32510)."