Left: pseudo-color image of source ID 018 from the Blanco Cosmology Survey in the gri bands. X-ray contours are overlaid in white. The green circle shows the estimated 0.5 × r₅₀₀. Right: color − magnitude diagram (r − z vs. z) for the cluster ID 018. The red points show the member galaxies used for the photo-z estimate and the red dotted line indicates the single stellar population model at cluster redshift z = 0.39 (see text for details).