Carroll1992

class hmf.cosmology.growth_factor.Carroll1992(*args, **kwargs)

Analytic approximation for the growth factor from Carroll et al. 1992.

This formula is based on a formula in Lahav+1991 and Schechter and Lightman 1991.

This formula is explicitly only valid at z=0, and a warning will be raised if you try to use it at z>0. However, the formula is actually pretty accurate at non-zero redshifts if redshift-dependent values for Omega_m and Omega_L are used.

Attributes

Methods

__init__(*args, **kwargs)

dlne_dlna(z)

Compute the derivative of ln(E(a)) with respect to ln(a).

This is useful for the growth factor, which has terms \(E'(a)/E(a) \equiv (1/a)*dlnE/dlna\) in its definition.

This implementation simply uses the exact definition from astropy of E(a) and writes down the derivative analytically.

classmethod get_models() → dict[str, type]

Get a dictionary of all implemented models for this component.

growth_factor(z)

Compute the normalized growth factor, \(D(a) = D^+(a)/D^+(a=1)\).

Parameters:

z (array_like) – Redshift.

Returns:

gf – The growth factor at z.

Return type:

array_like

growth_rate(z) → float | ndarray

Compute the growth rate, \(f(a) = d\ln D^+ / d\ln a\).

Parameters:

z (array_like) – Redshift.

Returns:

gr – The growth rate at z.

Return type:

array_like

radiation_density(z)

The fractional radiation density as a function of redshift.