The z_p distributions for the IR-emitting galaxies with available z in the supercluster field. The solid black (respectively, dashed blue) histogram represents the z_p distribution for the galaxies selected as members (respectively, not selected as members) on the basis of their z. The two vertical red dash-dotted lines identify the lower and upper z_p limits used to identify supercluster members in the sample of galaxies without z (not shown here).