Linear Growth of Cosmological Structure

Class providing the linear growth factor \(D(t)\) and its derivatives, which describe how matter density perturbations grow in the linear regime. The growth factor is used to normalize the power spectrum and to relate the amplitude of perturbations at different epochs. Implementations may treat different matter components (dark matter, baryons, radiation) and different approximations to the growth equation.

Default implementation: linearGrowthCollisionlessMatter

Methods

value → double precision

Return the linear growth factor at the given time and mass.

  • double precision time (optional) [in]

  • double precision expansionFactor (optional) [in]

  • logical collapsing (optional) [in]

  • type(enumerationNormalizeType) normalize (optional) [in]

  • type(enumerationComponentType) component (optional) [in]

  • double precision wavenumber (optional) [in]

logarithmicDerivativeExpansionFactor → double precision

Return the logarithmic derivative of linear growth factor with respect to expansion factor.

  • double precision time (optional) [in]

  • double precision expansionFactor (optional) [in]

  • logical collapsing (optional) [in]

  • type(enumerationComponentType) component (optional) [in]

  • double precision wavenumber (optional) [in]

logarithmicDerivativeWavenumber → double precision

Return the logarithmic derivative of linear growth factor with respect to wavenumber.

  • double precision time (optional) [in]

  • double precision expansionFactor (optional) [in]

  • logical collapsing (optional) [in]

  • type(enumerationComponentType) component (optional) [in]

  • double precision wavenumber (optional) [in]

isWavenumberDependent → logical

Return true if the growth function is wavenumber-dependent.

  • type(enumerationComponentType) component (optional) [in]

linearGrowthBaryonsDarkMatter

Linear growth of cosmological density perturbations in models containing both baryons and collisionless dark matter, computed by numerically integrating the coupled growth equations. Radiation perturbation growth is neglected. The integration is initialized at the redshift [redshiftInitial] and can use CAMB to set transfer function wavenumber sampling.

Methods

retabulate

Tabulate linear growth factor.

  • double precision time [in]

  • double precision wavenumber (optional) [in]

fileWrite

Read the tabulated mass variance from file.

fileRead

Read the tabulated mass variance from file.

remakeTable → logical

Return true if the table must be remade.

  • double precision time [in]

Parameters

  • [redshiftInitial] (real; default 100.0d0) — The initial redshift from which integration of linear growth should be begin.

  • [redshiftInitialDelta] (real; default 1.0d0) — The initial step in redshift used to estimate growth rates of perturbations using finite differencing.

  • [cambCountPerDecade] (integer; default 0) — The number of points per decade of wavenumber to compute in the CAMB transfer function. A value of 0 allows CAMB to choose what it considers to be optimal spacing of wavenumbers.

  • [darkMatterOnlyInitialConditions] (boolean; default .false.) — If true, set the initial conditions for baryonic modes using the dark matter mode initial conditions.

linearGrowthCollisionlessMatter

A linear growth of cosmological structure class for models consisting of only collisionless matter. Pressure terms for the growth of baryons are ignored, and there is no wavenumber dependence. It further assumes no growth of radiation perturbations.

(Default implementation)

Methods

retabulate

Tabulate linear growth factor.

  • double precision time [in]

linearGrowthNonClusteringBaryonsDarkMatter

Linear growth of cosmological structure in the limit where baryons do not cluster (i.e. small scales), and so has no wavenumber dependence. Also assumes no growth of radiation perturbations.

Methods

retabulate

Tabulate linear growth factor.

  • double precision time [in]