Top: spectra of secure cluster members for XMMU J0302.2-0001 (left, z = 1.185) and XMMU J1532.2-0836 (right, z = 1.358) smoothed with a 7 pixel boxcar filter. The expected observed positions of prominent spectral features at the median redshift are indicated by black dashed lines. The sky spectrum (bottom) and telluric features (top) are overplotted in red. For the BCGs (top panels) we display an overlaid LRG template spectrum in blue. Bottom: distribution of VLT/FORS2 galaxy spectra for the two clusters. The red hashed parts show the distribution of the red galaxies for both clusters (also shown in the insets), selected by requiring the redshift to be within z_CL  ±  0.015. The black hashed peak in the left panel (at z ≈ 0.65) corresponds to cluster XMMU J0302.1-0000 (see Appendix A). See also Sect. 2.2.2 for discussion.