Method

NumCosmoDistancedsound_horizon_dz

Declaration [src]

gdouble
nc_distance_dsound_horizon_dz (
  NcDistance* dist,
  NcHICosmo* cosmo,
  const gdouble z
)

Description [src]

Calculate the sound horizon [nc_distance_sound_horizon()] derivative with respect to $z$, $$\frac{d r_s(z)}{dz} = - \frac{c_s(z)}{E(z)}\, ,$$ where $c_s = \sqrt{c^{b\gamma 2}_s(z)}$ is the baryon-photon plasma speed of sound (see nc_hicosmo_bgp_cs2() for more details) and $E(z)$ is the normalized Hubble function [nc_hicosmo_E()].

Parameters

cosmo

Type: NcHICosmo

A NcHICosmo.

The data is owned by the caller of the method.
z

Type: const gdouble

Redshift $z$.

Return value

Type: gdouble

$\frac{d r_s(z)}{dz}$.