.. _physics-cosmologyParameters:

Cosmological Parameters
=======================

Object providing the fundamental cosmological parameters that describe the background Universe: matter density :math:`\Omega_\mathrm{m}`, dark energy density :math:`\Omega_\Lambda`, baryon density :math:`\Omega_\mathrm{b}`, radiation density :math:`\Omega_\mathrm{r}`, curvature :math:`\Omega_k`, Hubble constant :math:`H_0`, and CMB temperature :math:`T_\mathrm{CMB}`. These parameters are used throughout Galacticus to compute cosmological distances, times, and densities.

**Default implementation:** ``cosmologyParametersSimple``

Methods
-------

``OmegaMatter`` → ``double precision``
   Return the cosmological matter density in units of the critical density at the present day.

``OmegaDarkEnergy`` → ``double precision``
   Return the cosmological dark energy density in units of the critical density at the present day.

``OmegaBaryon`` → ``double precision``
   Return the cosmological baryon density in units of the critical density at the present day.

``OmegaRadiation`` → ``double precision``
   Return the cosmological radiation density in units of the critical density at the present day.

``OmegaCurvature`` → ``double precision``
   Return the cosmological curvature density in units of the critical density at the present day.

``HubbleConstant`` → ``double precision``
   Return the Hubble constant at the present day. The optional ``units`` argument specifies if the return value should be in units of km/s/Mpc (hubbleUnitsStandard), Gyr\ :math:`^{-1}` (hubbleUnitsTime), or 100 km/s/Mpc (hubbleUnitsLittleH).

   * ``type(enumerationHubbleUnitsType), intent(in ), optional :: units``

``temperatureCMB`` → ``double precision``
   Return the temperature of the cosmic microwave background radiation (in units of Kelvin) at the present day.

``densityCritical`` → ``double precision``
   Return the critical density at the present day in units of :math:`\mathrm{M}_\odot/`\ Mpc\ :math:`^3`.

.. _physics-cosmologyParametersSimple:

``cosmologyParametersSimple``
-----------------------------

Provides basic cosmological parameters including the matter density :math:`\Omega_\mathrm{M}`, baryon density :math:`\Omega_\mathrm{b}`, dark energy density :math:`\Omega_\Lambda`, :term:`CMB` temperature :math:`T_\mathrm{CMB}`, and Hubble constant :math:`H_0`, all specified as input parameters. Also computes derived quantities including the curvature density :math:`\Omega_\mathrm{K}`, radiation density :math:`\Omega_\mathrm{r}`, and critical density :math:`\rho_\mathrm{crit}`.

**(Default implementation)**

**Methods**

* ``calculationReset`` — Reset memoized calculations.

**Parameters**

* ``[OmegaMatter]`` (real; default ``0.3153d0``) — The density of matter in the Universe in units of the critical density.
* ``[OmegaBaryon]`` (real; default ``0.04930d0``) — The density of baryons in the Universe in units of the critical density.
* ``[OmegaDarkEnergy]`` (real; default ``0.6847d0``) — The density of dark energy in the Universe in units of the critical density.
* ``[temperatureCMB]`` (real; default ``2.72548d0``) — The present day temperature of the :term:`CMB` in units of Kelvin.
* ``[HubbleConstant]`` (real; default ``67.36d0``) — The present day value of the Hubble parameter in units of km/s/Mpc.