cogwheel.cosmology.comoving_to_luminosity_diff_vt_ratio

cogwheel.cosmology.comoving_to_luminosity_diff_vt_ratio(d_luminosity)

Return ratio of differential comoving volume-time to luminosity- volume and observer-time.

Compute the ratio:

\[\frac{d(V_C t_C)}{d(V_L t)} = (1+z)^{-4} (1 - \frac{d_L}{1+z} \frac{dz}{dd_L})\]

where \((V_C t_C)\) is the comoving volume-time, \(V_L\) is the luminosity volume, \(t\) is the present-day observer time, \(z\) is the cosmological redshift, \(d_L\) the luminosity distance and \(dz/dd_L\) the derivative of redshift with respect to luminosity distance.