Radial spectroscopic coverage of one confirmed cluster. Each filled circle represents one red-sequence galaxy with p_mem > 0.05. The x-axis is their projected distance to the X-ray centre, normalized by R_λ. Spectroscopically identified members are displayed at y = 1 and coloured in black (p_i = 1), and interlopers are displayed at y = 0 and coloured in white (p_i = 0). Galaxies not assigned a spectroscopic redshift are coloured according to their p_mem value (p_i = p_mem). The dashed red line shows the completeness rate, S(< x) (Eq. (1)) within radius x. The dotted line indicates the virial radius estimated from an X-ray luminosity–mass relation.