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 , intent(in ), optional :: time , expansionFactor

  • logical , intent(in ), optional :: collapsing

  • type (enumerationNormalizeType), intent(in ), optional :: normalize

  • type (enumerationComponentType), intent(in ), optional :: component

  • double precision , intent(in ), optional :: wavenumber

logarithmicDerivativeExpansionFactor → double precision

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

  • double precision , intent(in ), optional :: time , expansionFactor

  • logical , intent(in ), optional :: collapsing

  • type (enumerationComponentType), intent(in ), optional :: component

  • double precision , intent(in ), optional :: wavenumber

logarithmicDerivativeWavenumber → double precision

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

  • double precision , intent(in ), optional :: time , expansionFactor

  • logical , intent(in ), optional :: collapsing

  • type (enumerationComponentType), intent(in ), optional :: component

  • double precision , intent(in ), optional :: wavenumber

isWavenumberDependent → logical

Return true if the growth function is wavenumber-dependent.

  • type(enumerationComponentType), intent(in ), optional :: component

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.

  • fileWrite — Read the tabulated mass variance from file.

  • fileRead — Read the tabulated mass variance from file.

  • remakeTable — Return true if the table must be remade.

Parameters

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

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

  • [cambCountPerDecade] (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] (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.

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.