Galaxy clusters show pronounced bimodal distribution between Cool Core (dense rapidly cooling centers) and Non-Cool Core (flat high-entropy cores) systems. Mergers should disrupt cool cores but simulations struggle with NCC abundance + CC resilience to all but major head-on collisions. Cooling flow problem: predicted massive cold-gas inflow not observed in CCs, demanding fine-tuned AGN feedback regulation over Gyr (Fabian 2012; McDonald 2018).
The standard model has cluster centers regulated by AGN-feedback + radiative-cooling balance. Recovering the sharp CC/NCC dichotomy + the resilience of CCs demands fine-tuned AGN duty cycles + jet opening angles + cooling-flow feedback regulation. The model has no clean source for the bimodality.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, the cool-core dichotomy is a cascade-thermodynamic + Plasma Equivalence signature. The cluster initial conditions at the cascade epoch (P22, P23, P25) determine future CC/NCC status: cluster-progenitors with low-impact-parameter cascade depositions (high-density compact cascade-thermalized matter) become Cool Cores; high-impact-parameter cascade depositions (more diffuse cascade-thermalized matter) become Non-Cool Cores.
The Plasma Equivalence Theorem (P29, P30) preserves the cascade-deposited thermodynamic state through cluster assembly, locking in the CC/NCC bimodality at deposition rather than evolving through stochastic merger histories. Cluster mergers can disrupt CCs into NCCs at the highest collision energies, but the underlying CC/NCC distinction is set at cascade-deposition. This explains both the sharpness of the dichotomy and the resilience of CCs to typical mergers.
The cooling-flow problem dissolves because the cascade-relic entropy (P29, P30, recid 126) provides a baseline cooling resistance: cooling flows do not run away because the inherited cascade entropy keeps the central gas above the threshold for catastrophic infall. Standard AGN feedback then provides the smaller-scale ongoing regulation. Gravitational superposition (P50, P51, P52) gives apparent dynamics. The same M2 framework that resolves the y-distortion deficit (recid 26), the polarization-bump anomaly (recid 39), the ICM entropy floor (recid 126), and the broader cascade-thermodynamic cluster signatures accounts for cool-core dichotomy.
If precision Athena + Lynx + future X-ray surveys find CC/NCC distribution fully reproducible by AGN-feedback + standard-cooling-flow predictions at the 5% level (no cascade-thermodynamic initial-condition signature, no inherited cascade-entropy floor effect), the M2 cascade-thermodynamic explanation is refuted. The signature SCT prediction is the dichotomy correlating with cascade-deposition geometry rather than with merger-history stochasticity.