Evolution of T/T_c in the halo center during collapse for various masses and initial temperatures with g = 10⁻⁵ eV⁻² and L = 100 kpc. Both the evolution with entropy production (solid lines) and without (striped lines) are shown until the overdensity reach 10⁵. The two cases differ only in the end stage of the collapse, well after the critical velocity is first reached, indicated by the colored vertical lines.