TITLE: GCN CIRCULAR NUMBER: 32542 SUBJECT: GRB 220831A: Gemini-South Infrared Observations DATE: 22/09/10 20:56:20 GMT FROM: Brendan O'Connor at UMD B. O'Connor (UMD/GWU), E. Troja (UTV/ASU), S. Dichiara (PSU), on behalf of a larger collaboration: We performed target of opportunity observations of GRB 220831A (Tohuvavohu et al. GCN 32506) with the FLAMINGOS-2 spectrograph mounted on the Gemini-South telescope. Observations were taken in the J and Ks filters with total exposure of 1785 and 1635 s, respectively. The observations began at 2022-09-09 03:27:01 UT, corresponding to ~8.6 d after the burst. Further observations were obtained the following night (~9.6 d) in J-band for 2000 s exposure. At the location of the optical, infrared, and X-ray counterpart (Dichiara et al. GCN 32510, D'Avanzo et al. GCN 32513, Freeburn et al. GCN 32516, Gordon et al. GCN 32535), we detect a faint source with brightness J ~ 24.5 AB mag. This result confirms the fading of the infrared source reported by D'Avanzo et al. GCN 32513. Our measurement implies a very red color, r-J >2, of the late time emission. At present it is not clear whether this is due to the onset of a kilonova or to the contribution of an underlying host galaxy. Assuming a behavior similar to AT2017gfo, the apparent J-band magnitude implies a distance of ~200 Mpc. However, the nearby galaxy noted by D’Avanzo et al. GCN 32513 is significantly closer at only 4 Mpc. If instead the source is dominated by the host galaxy contribution, the red color suggests that GRB 220831A was a distant event (see, e.g., O'Connor et al. 2022, MNRAS, 515, 4890). Further observations are planned. Magnitudes are calibrated against stars in the 2MASS catalog and are not corrected for Galactic extinction. We thank the staff of the Gemini Observatory, in particular Joan Font-Serra and Yijung Kang, for rapid scheduling of these observations.