Reference

This page contains a list of all methods and attributes that a Cosmology instance might support.

Each item on this list is described in an associated protocol.

Hubble parameter

h	Hubble parameter \(h\) today.
H(z, /)	Hubble parameter \(H(z)\) in km s-1 Mpc-1.
H0	Hubble parameter at redshift 0 in km s-1 Mpc-1.
H_over_H0(z, /)	Standardised Hubble function \(E(z) = H(z)/H_0\).
scale_factor(z, /)	Redshift-dependenct scale factor.
scale_factor0	Scale factor at z=0.

Distance

angular_diameter_distance(...)	Angular diameter distance \(d_A\) in Mpc.
comoving_distance(...)	Comoving line-of-sight distance \(d_c\) in Mpc.
hubble_distance	Hubble distance in Mpc.
lookback_distance(...)	Lookback distance \(d_T\) in Mpc.
luminosity_distance(...)	Redshift-dependent luminosity distance \(d_L\) in Mpc.
proper_distance(...)	Proper distance \(d\) in Mpc.
transverse_comoving_distance(...)	Transverse comoving distance \(d_M\) in Mpc.

Inverse distance

These functions return a redshift given a distance.

inv_comoving_distance(dc, /)

Redshift at a given comoving line-of-sight distance.

Volume

comoving_volume(...)	Comoving volume \(V_c\) in Mpc3.
differential_comoving_volume(z, /)	Differential comoving volume in Mpc3 per steradian.

Time

age(z, /)	Age of the universe at redshift z in Gyr.
hubble_time	Hubble time in Gyr.
proper_time(-> ~cosmology.api._array_api.Array)	Proper time \(t\) in Gyr.
lookback_time(-> ~cosmology.api._array_api.Array)	Lookback time in Gyr.

Density

Omega_tot(z, /)	Redshift-dependent total density parameter.
Omega_tot0	Omega total; the total density/critical density at z=0.
critical_density(z, /)	Redshift-dependent critical density in Msol Mpc-3.
critical_density0	Critical density at z = 0 in Msol Mpc-3.

Matter

Omega_b(z, /)	Redshift-dependent baryon density parameter.
Omega_b0	Omega baryon; the baryon density/critical density at z=0.
Omega_dm(z, /)	Redshift-dependent dark matter density parameter.
Omega_dm0	Omega dark matter; the dark matter density/critical density at z=0.
Omega_m(z, /)	Redshift-dependent matter density parameter.
Omega_m0	Omega matter; the matter density/critical density at z=0.

Dark energy

Omega_de(z, /)	Redshift-dependent dark energy density parameter.
Omega_de0	Omega dark energy; the dark energy density/critical density at z=0.

Radiation

Omega_gamma(z, /)	Redshift-dependent photon density parameter.
Omega_gamma0	Omega gamma; the photon density/critical density at z=0.

Neutrinos

Neff	Effective number of neutrino species.
Omega_nu(z, /)	Redshift-dependent neutrino density parameter.
Omega_nu0	Omega neutrino; the neutrino density/critical density at z=0.
m_nu	Neutrino mass(es) in eV.

Curvature

Omega_k(z, /)	Redshift-dependent curvature density parameter.
Omega_k0	Omega curvature; the effective curvature density/critical density at z=0.

Cosmic microwave background

T_cmb(z, /)	CMB temperature in K at redshift z.
T_cmb0	CMB temperature in K at z=0.

Perturbations

growth_factor(z, /)

Growth factor \(D(z)\) at redshift \(z\).