Function visibility_j_bb_star

pub fn visibility_j_bb_star(z: f64) -> f64

Improved thermalization visibility with correction factor.

J_bb*(z) = 0.983 · J_bb(z) · (1 − 0.0381 (z/z_μ)^{2.29})

Chluba (2015), arXiv:1506.06582, Eq. 13. Valid for 3×10⁵ ≲ z ≲ 6×10⁶ in the standard cosmology (Chluba 2014 fit, neglecting relativistic temperature corrections which become noticeable at z_i ≳ 4×10⁶). The prefactor 0.983 absorbs the small residual blackbody mismatch during the μ-era. The base J_bb exponent (5/2) and z_μ are analytically derived (see visibility_j_bb).