Numerical solutions of gas density and baryon fraction, when the self‐gravity of the gas is included, for two choices of the central density, ﹩\delta _{c}=\rho _{0}/ \rho _{c}﹩, and the universal baryon fraction, ﹩f_{b,\mathrm{BBN}\,}﹩. The best‐fit β model to each curve is plotted by open squares. The corresponding parameters are summarized in Table 1.