Protocluster dark matter halo mass as a function of redshift for the protoclusters in the Cosmos field at z ≃ 2 listed in Table 9 as annotated, and for the G237 substructures (ss1: magenta full star, ss2: red full star). The dashed black lines represent the average halo mass growth based on the fitting functions formulated by Behroozi et al. (2013). Thick lines indicate different gas cooling regimes as predicted by Dekel & Birnboim (2006): below a critical halo mass of (red curve) inflowing gas is predominantly cold allowing galaxies to grow (in addition to merging); above (red curve), and below a critical redshift, z^crit (to the left of the blue line), cold gas flows are shock-heated, thus shutting off most of the gas supply to the galaxies; above (red curve), and above z^crit (to the right of the blue line) cold gas is able to penetrate the hot gas environment through cold flow streams favoring galaxy growth and star formation.