NumCosmoDistancedecoupling_redshift

The decoupling redshift $z_\star$ corresponds to the epoch of the last scattering surface of the cosmic microwave background photons.

This function computes $z_\star$ using [nc_hicosmo_z_lss()], if cosmo implements it, or using Hu & Sugiyama fitting formula [Hu (1996)][XHu1996][arXiv], $$ z_\star = 1048 \left(1 + 1.24 \times 10^{-3} (\Omega_{b0} h^2)^{-0.738}\right) \left(1 + g_1 (\Omega_{m0} h^2)^{g_2}\right),$$ where $\Omega_{b0} h^2$ [nc_hicosmo_Omega_b0h2()] and $\Omega_{m0} h^2$ [nc_hicosmo_Omega_m0h2()] are, respectively, the baryonic and matter density parameters times the square of the dimensionless Hubble parameter $h$, $H_0 = 100 \, h \, \text{km/s} \, \text{Mpc}^{-1}$. The parameters $g_1$ and $g_2$ are given by $$g_1 = \frac{0.0783 (\Omega_{b0} h^2)^{-0.238}}{(1 + 39.5 (\Omega_{b0} h^2)^{0.763})} \; \text{and} \; g_2 = \frac{0.56}{\left(1 + 21.1 (\Omega_{b0} h^2)^{1.81}\right)}.$$.