Top left: overview of the VIS³COS survey showing the galaxy overdensity and targeted galaxies at 0.8 <  z <  0.9 with spectroscopic redshifts (white crosses) along with the location of known X-ray clusters (empty red circles, Finoguenov et al. 2007). Bottom left: NUV-r-J diagram (derived using Laigle et al. 2016 photometry) for galaxies in our survey, with the separation between quiescent (red circles) and star-forming (blue diamonds) as defined by Ilbert et al. (2013) shown as a solid line. We show the average error on each colour as a black cross. Right panels: examples of HST/ACS F814W 4″ × 4″ rest-frame B-band images (Koekemoer et al. 2007) of eight of our sources with individual information on stellar mass, SFR, and local overdensity in each panel. We highlight the position of these eight galaxies with large numbered black circles in the left panels.