Large-scale structure around the position of SN 2021hem (marked with a cyan cross) shown in a field with a size of 2 × 2 square degrees (DSS image). The colored circles indicate the galaxies with measured redshifts from the SIMBAD catalog within a redshift range of 0.02 to 0.05. The color bar indicates the redshifts for each color. There appears to be an overdensity of galaxies with redshifts close to z ≈ 0.027, ≈0.035 within a radius of 1 Mpc from the position of the SN. The open star symbol corresponds to the AGN galaxy 2MASX J16212572+1431537, which lies at a projected distance of 104 kpc from the SN.