LambdaCDM

class astropy.cosmology.core.LambdaCDM(H0, Om0, Ode0, Tcmb0=2.725, Neff=3.04, name='LambdaCDM') [edit on github][source]

Bases: astropy.cosmology.core.FLRW

FLRW cosmology with a cosmological constant and curvature.

This has no additional attributes beyond those of FLRW.

Examples

>>> from astro.cosmology import LambdaCDM
>>> cosmo = LambdaCDM(H0=70, Om0=0.3, Ode0=0.7)

The comoving distance in Mpc at redshift z:

>>> dc = cosmo.comoving_distance(z)

Methods Summary

efunc(z) Function used to calculate H(z), the Hubble parameter.
inv_efunc(z) Function used to calculate \frac{1}{H_z}.
w(z) Returns dark energy equation of state at redshift z.
de_density_scale(z) Evaluates the redshift dependence of the dark energy density.

Methods Documentation

efunc(z) [edit on github][source]

Function used to calculate H(z), the Hubble parameter.

Parameters :

z : array_like

Input redshifts.

Returns :

E : ndarray, or float if input scalar

The redshift scaling of the Hubble consant.

Notes

The return value, E, is defined such that H(z) = H_0 E.

inv_efunc(z) [edit on github][source]

Function used to calculate \frac{1}{H_z}.

Parameters :

z : array_like

Input redshifts.

Returns :

E : ndarray, or float if input scalar

The inverse redshift scaling of the Hubble constant.

Notes

The return value, E, is defined such that H_z = H_0 /
E.

w(z) [edit on github][source]

Returns dark energy equation of state at redshift z.

Parameters :

z : array_like

Input redshifts.

Returns :

w : ndarray, or float if input scalar

The dark energy equation of state

Notes

The dark energy equation of state is defined as w(z) = P(z)/\rho(z), where P(z) is the pressure at redshift z and \rho(z) is the density at redshift z, both in units where c=1. Here this is w(z) = -1.

de_density_scale(z) [edit on github][source]

Evaluates the redshift dependence of the dark energy density.

Parameters :

z : array_like

Input redshifts.

Returns :

I : ndarray, or float if input scalar

The scaling of the energy density of dark energy with redshift.

Notes

The scaling factor, I, is defined by \rho(z) = \rho_0 I, and in this case is given by I = 1.

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