GCN Circular 27833
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), and D. A. Kann (HETH/IAA-CSIC) report: Within the XRT error circle of GRB 200528A (Fermi GBM team, GCN #27831; Ambrosi et al., GCN #27832), a bright, extended object is detected, at position (J2000, from SDSS): RA = 176.64297 Dec. = 58.19313 It is found to have (from SDSS): u' = 22.28 +/-0.42 mag; g' = 21.46 +/- 0.075 mag; r' = 20.45 +/- 0.047 mag; i' = 20.13 +/- 0.052 mag; z' = 19.88 +/- 0.147 mag. It is also detected in PanSTARRS and WISE with W1 = 16.7 +/- 0.1 mag. The photometric redshift in SDSS is given as z = 0.380 +/- 0.0792. We suggest this galaxy to be the host galaxy of GRB 200528A. The early non-detection in UVOT indicates this might be an optically dark GRB, as the X-ray light curve is very bright early on. The X-ray column density is unknown so far (Ambrosi et al., GCN #27832) but likely to be high. Confirmation or rejection awaits a refined XRT position once data are obtainable in PC mode.