The fraction of pure star-forming galaxies and sources with AGN contribution, as a function of cluster-centric distance. Samples are matched in Hα luminosity between 10⁴⁰ and 10⁴² erg s⁻¹. In merging clusters, the fraction of line emitters powered by SF is constant with radial distance. In relaxed clusters, the fraction of purely star-forming galaxies drops within 3 Mpc of the cluster core. The fractions of AGNs and SF at relaxed cluster outskirts match those in the field (e.g., Kauffmann et al. 2003; Shioya et al. 2008; Hayashi et al. 2018).