Cooling Times

Class providing models of the cooling time (in Gyr) for gas in the hot halo surrounding a galaxy, defined as the ratio of the thermal energy density to the radiative cooling rate. Given temperature, density, elemental abundances, chemical species densities, and an ambient radiation field, implementations typically evaluate \(t_\mathrm{cool} = (3/2) n k_\mathrm{B} T / \mathcal{L}\). The logarithmic gradients with respect to density and temperature are also provided for use in implicit ODE solvers that integrate the cooling flow equations.

Default implementation: coolingTimeSimple

Methods

time → double precision

Returns the cooling time for gas in the hot atmosphere surrounding the galaxy in units of Gyr.

  • type (treeNode ), intent(inout) :: node

  • double precision , intent(in ) :: temperature , density

  • type (abundances ), intent(in ) :: gasAbundances

  • type (chemicalAbundances ), intent(in ) :: chemicalDensities

  • class (radiationFieldClass), intent(inout) :: radiation

gradientDensityLogarithmic → double precision

Returns the logarithmic derivative of cooling time with respect to density for gas in the hot atmosphere surrounding the galaxy.

  • type (treeNode ), intent(inout) :: node

  • double precision , intent(in ) :: temperature , density

  • type (abundances ), intent(in ) :: gasAbundances

  • type (chemicalAbundances ), intent(in ) :: chemicalDensities

  • class (radiationFieldClass), intent(inout) :: radiation

gradientTemperatureLogarithmic → double precision

Returns the logarithmic derivative of cooling time with respect to temperature for gas in the hot atmosphere surrounding the galaxy.

  • type (treeNode ), intent(inout) :: node

  • double precision , intent(in ) :: temperature , density

  • type (abundances ), intent(in ) :: gasAbundances

  • type (chemicalAbundances ), intent(in ) :: chemicalDensities

  • class (radiationFieldClass), intent(inout) :: radiation

coolingTimeSimple

A cooling time class in which the cooling time is simply

\[t_\mathrm{cool} = {N \over 2} {\mathrm{k}_\mathrm{B} T n_\mathrm{tot} \over \Lambda},\]

where \(N=\)[degreesOfFreedom] is the number of degrees of freedom in the cooling gas which has temperature \(T\) and total particle number density (including electrons) \(n_\mathrm{tot}\) and \(\Lambda\) is the cooling function.

(Default implementation)

Methods

  • calculationReset — Reset memoized calculations.

Parameters

  • [efficiencyWind] (default 2.2157d-3) — The coupling efficiency of the black hole accretion-driven wind, defined as the fraction of the accreted rest-mass energy that is deposited as kinetic or thermal energy into the surrounding gas via AGN-driven outflows.

  • [redshiftReionization] (default 9.97d0) — The redshift of reionization below which baryonic accretion onto halos is suppressed due to the ionizing background heating the intergalactic medium and preventing gas from accreting onto low-mass halos.

  • [opticalDepthReionization] — The optical depth to electron scattering below which baryonic accretion is suppressed.

  • [velocitySuppressionReionization] (default 35.0d0) — The velocity scale below which baryonic accretion is suppressed.

  • [accretionNegativeAllowed] (default .true.) — Specifies whether negative accretion (mass loss) is allowed in the simple halo accretion model.

  • [accretionNewGrowthOnly] (default .false.) — Specifies whether accretion from the IGM is allowed only when a halo is growing past its previous greatest mass.

  • [acceptedStateCount] (default 100) — The number of states to use in acceptance rate statistics.

  • [timeStepRelative] (default 0.1d0) — The maximum allowed relative change in time for a single step in the evolution of a node.

  • [timeStepAbsolute] (default 1.0d0) — The maximum allowed absolute change in time (in Gyr) for a single step in the evolution of a node.

  • [timeStepMinimum] (default 1.0d-6) — The smallest timestep to use in profiling ODE solver steps.

  • [timeStepMaximum] (default 1.0d+1) — The largest timestep to use in profiling ODE solver steps.

  • [timeStepPointsPerDecade] (default 3) — The number of bins per decade of timestep to use when profiling ODE solver steps.

  • [wavelength] (default 1.0d4) — The wavelength of the photon packet (in AA).

  • [wavelengthMinimum] (default 0.5d4) — The minimum wavelength of the photon packet (in AA).

  • [wavelengthMaximum] (default 2.0d4) — The maximum wavelength of the photon packet (in AA).

  • [luminosity] (default 1.0d0) — The luminosity of the photon packet (in \(L_\odot\)).

  • [massRatioMajorMerger] (default 0.25d0) — The mass ratio above which mergers are considered to be “major”.

  • [destinationGasMinorMerger] (default var_str('spheroid')) — The component to which satellite galaxy gas moves to as a result of a minor merger.

  • [destinationStarsMinorMerger] (default var_str('spheroid')) — The component to which satellite galaxy stars move to as a result of a minor merger.

  • [degreesOfFreedom] (default 3.0d0) — Number of degrees of freedom to assume when computing the energy density of cooling gas in the “simple” cooling time class.

  • [timeScale] (default 1.0d0) — The timescale (in Gyr) for cooling in the simple cooling rate model.

  • [reionizationRedshift] (default 9.97d0) — The redshift of reionization in the simple IGM state model.

  • [reionizationTemperature] (default 1.0d4) — The post-reionization temperature (in units of Kelvin) in the simple IGM state model.

  • [preReionizationTemperature] (default 10.0d0) — The pre-reionization temperature (in units of Kelvin) in the simple IGM state model.

  • [useFormationHalo] (default .false.) — Specifies whether or not the “formation halo” should be used when solving for the radii of galaxies.

  • [solveForInactiveProperties] (default .true.) — If true, galactic structure is solved for during evaluation of inactive property integrals. Otherwise, structure is not solved for during this phase—this should only be used if the inactive property integrands do not depend on galactic structure.

  • [rateFractionalMaximum] (default 10.0d0) — The maximum fractional mass loss rate per dynamical time in the simple model of mass loss due to tidal stripping.

  • [beta] (default 1.0d0) — The scaling factor which multiplies the tidal mass loss rate.

  • [OmegaMatter] (default 0.3153d0) — The density of matter in the Universe in units of the critical density.

  • [OmegaBaryon] (default 0.04930d0) — The density of baryons in the Universe in units of the critical density.

  • [OmegaDarkEnergy] (default 0.6847d0) — The density of dark energy in the Universe in units of the critical density.

  • [temperatureCMB] (default 2.72548d0) — The present day temperature of the CMB in units of Kelvin.

  • [HubbleConstant] (default 67.36d0) — The present day value of the Hubble parameter in units of km/s/Mpc.