Specific Angular Momenta of Cooling Gas

Class providing models of the specific angular momentum (in km s\(^{-1}\) Mpc) of gas cooling out of the hot halo and infalling onto the galaxy. The angular momentum of infalling gas determines the size and rotational structure of the galaxy disk that forms from it. Different implementations may assume solid-body rotation of the hot gas, track the angular momentum profile of the halo, or apply corrections for angular momentum transport during infall.

Default implementation: coolingSpecificAngularMomentumConstantRotation

Methods

angularMomentumSpecific → double precision

Return the specific angular momentum (in units of km/s Mpc) of cooling gas in node.

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

  • double precision , intent(in ) :: radius

coolingSpecificAngularMomentumConstantRotation

A cooling specific angular momentum class which assumes a constant rotation velocity as a function of radius. The specific angular momentum of cooling gas is given either by

\[j_\mathrm{cool} = \langle j \rangle r_\mathrm{cool} A,\]

where \(r_\mathrm{cool}\) is the cooling radius, \(A\) is the rotation normalization and \(\langle j \rangle\) is the mean specific angular momentum of the cooling gas, if [useInteriorMean]\(=\)false, or by

\[j_\mathrm{cool} = \langle j \rangle {I_3(r_\mathrm{cool})/I_2(r_\mathrm{cool})} A,\]

where \(I_n(r)\) is the \(n^\mathrm{th}\) radial moment of the hot gas density profile from \(0\) to \(r\) (this therefore gives the mean specific angular momentum interior to radius \(r\)), if [useInteriorMean]\(=\)true.

If [sourceAngularMomentumSpecificMean]\(=\)darkMatter then \(\langle j \rangle\) is the mean specific angular momentum of the dark matter halo, while if [sourceAngularMomentumSpecificMean]\(=\)hotGas then \(\langle j \rangle\) is equal to the mean specific angular momentum of gas currently in the hot gas reservoir. If [sourceNormalizationRotation]\(=\)darkMatter then the rotation normalization \(A\) is computed using the dark matter density profile, while if [sourceNormalizationRotation]\(=\)hotGas it is computed using the density profile of the hot gas reservoir.

(Default implementation)

Methods

  • calculationReset — Reset memoized calculations.

Parameters

  • [sourceAngularMomentumSpecificMean] (default var_str('hotGas')) — The component (”hotGas” or “darkMatter”) from which the mean specific angular momentum should be computed for calculations of cooling gas specific angular momentum.

  • [sourceNormalizationRotation] (default var_str('hotGas')) — The component (”hotGas” or “darkMatter”) from which the constant rotation speed should be computed for calculations of cooling gas specific angular momentum.

  • [useInteriorMean] (default .false.) — Specifies whether to use the specific angular momentum at the cooling radius, or the mean specific angular momentum interior to that radius.

coolingSpecificAngularMomentumMean

A cooling specific angular momentum class in which the specific angular momentum of cooling gas is given by

\[j_\mathrm{cool} = J_\mathrm{hot}/M_\mathrm{hot},\]

where \(J_\mathrm{hot}\) and \(M_\mathrm{hot}\) are the total angular momentum and mass of the hot halo respectively.