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.