Cooling Time Available

Class providing models of the time available for cooling (in Gyr)—the elapsed time since gas in the hot halo was first able to start cooling. This quantity, together with the cooling time, determines whether gas has had enough time to cool and fall in. Implementations typically anchor this time to halo formation or to the time since the last major merger, and different choices lead to significantly different predictions for the cold gas supply and star formation history of galaxies.

Default implementation: coolingTimeAvailableWhiteFrenk1991

Methods

timeAvailable → double precision

Return the time available for cooling in node in units of Gyr.

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

timeAvailableIncreaseRate → double precision

Return the rate at which the time available for cooling increases in node (dimensionless).

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

coolingTimeAvailableBensonBower2010

A time available for cooling class implementing the model of Benson and Bower (2010).

coolingTimeAvailableFormationTime

A time available for cooling class which implements the algorithm of Cole et al. (2000), that is, the time available is equal to

\[t_\mathrm{available} = t - t_\mathrm{form},\]

where \(t_\mathrm{form}\) is the time at which the halo formed.

coolingTimeAvailableWhiteFrenk1991

A time available for cooling class which implements the algorithm of White and Frenk (1991). The time available for cooling is equal to

\[t_\mathrm{available} = \exp\left[ f \ln t_\mathrm{Universe} + (1-f)\ln t_\mathrm{dynamical} \right],\]

where \(f=\)[ageFactor] is an interpolating factor, \(t_\mathrm{Universe}\) is the age of the Universe and \(t_\mathrm{dynamical}\) is the dynamical time in the halo. The original White and Frenk (1991) algorithm corresponds to \(f=1\).

(Default implementation)

Parameters

  • [ageFactor] (default 0.0d0) — Interpolates (geometrically) between the age of the Universe and the halo dynamical time for the time available for cooling in the White and Frenk (1991) method.

  • [velocityCutOff] (default 1.0d4) — The halo virial velocity (in km/s) above which cooling rates are forced to zero in the White and Frenk (1991) cooling rate model.