Merger Tree Building Mass Resolutions

Class providing the minimum progenitor halo mass (mass resolution) to resolve when building a merger tree. Branches below this mass are not followed individually; instead their accreted mass is treated as smooth, unresolved accretion onto the main progenitor. The mass resolution controls the trade-off between completeness of the merger history and computational cost, and can be set as a fixed value, a fraction of the root halo mass, or adaptively based on tree size.

Default implementation: mergerTreeMassResolutionFixed

Methods

resolution → double precision

Gives the mass resolution to use for the given tree.

  • type(mergerTree), intent(in ) :: tree

mergerTreeMassResolutionFixed

A merger tree mass resolution class which assumes a fixed, uniform mass resolution applied to all merger trees during tree construction. The minimum resolved halo mass is set by the [massResolution] parameter, expressed in Solar masses, below which branches are not built.

(Default implementation)

Parameters

  • [massResolution] (real; default 5.0d9) — The mass resolution to use when building merger trees.

mergerTreeMassResolutionScaled

A merger tree mass resolution class which computes the mass resolution to be min([massResolutionMaximum],max([massResolutionMinimum],[massResolutionFractional]\(\times M_\mathrm{base}\))), where \(M_\mathrm{base}\) is the base mass of the merger tree.

Parameters

  • [massResolutionMinimum] (real; default 5.0d9) — The minimum mass resolution to use when building merger trees.

  • [massResolutionMaximum] (real; default huge(0.0d0)) — The maximum mass resolution to use when building merger trees.

  • [massResolutionFractional] (real; default 1.0d-3) — The fraction of the tree’s root node mass to be used for the mass resolution when building merger trees.