Environmental quenching—where interactions with other galaxies and/or the intracluster medium suppress star formation in low-mass galaxies—has been well established as the primary driver behind the formation of the red sequence for low-mass galaxies within clusters at low redshift (z 2 protoclusters have yet to virialize and develop a dense enough environment required to efficiently quench low-mass galaxies.
Pan et al. (Fri,) studied this question.