Joel Primack helped formulate cold dark matter as a quantitative framework for galaxy formation. The 1984 study with George R. Blumenthal, Sandra Faber and Martin Rees linked a primordial fluctuation spectrum to the formation of galaxies and galaxy clusters when collisionless particles have sufficiently small early velocity dispersion.[ref]
Formation of galaxies and large-scale structure with cold dark matter by George R. Blumenthal and others. Abstract and introductory formulation of cold collisionless matter
Here “cold” concerns the particles' early random velocities, not whether the later galaxies are thermally cold.
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