Sky distribution of galaxies in SCl A2142. The red symbols show galaxies with old stellar populations (D_n(4000)≥1.55), and the blue symbols denote galaxies with young stellar populations (D_n(4000)< 1.55). The first number shows the percentage of galaxies with old stellar populations divided by D_n(4000) index in rich groups. The second number shows the median age of galaxy populations in a group (in Gyr, Table 2). Galaxies in rich groups are denoted with filled circles. The crosses denote galaxies in poor groups with 2 − 9 galaxies, and single galaxies. The green triangles show recently quenched galaxies, and orange stars indicate the positions of AGNs. The orange circle has a radius of about 8 h⁻¹ Mpc (in sky projection). The dashed line shows the supercluster axis.