Dark Matter Halo Biases

Class providing models of the linear bias factor \(b(M, t)\) of dark matter halos—the ratio of halo-to-matter overdensity on large scales, describing how strongly halos cluster relative to the underlying dark matter distribution. More massive halos form in rarer, higher-\(\nu\) peaks and are therefore more strongly biased. The bias enters the two-halo term of the halo model power spectrum, void-galaxy cross-correlations, and galaxy clustering predictions. Implementations typically follow analytic fitting functions (e.g.Tinker et al. 2010) calibrated to N-body simulations as a function of halo mass and redshift.

Default implementation: darkMatterHaloBiasTinker2010

Methods

biasByMass → double precision

Returns the bias of a halo specified by a mass (in \(\mathrm{M}_\odot\)) and time (in Gyr).

• double precision, intent(in ) :: mass, time

• double precision, intent(in ), optional :: radius

biasByNode → double precision

Returns the large-scale linear bias factor \(b\) of the dark matter halo represented by the supplied node, extracted from the node’s basic component for its mass and formation time.

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

• double precision , intent(in ), optional :: radius

darkMatterHaloBiasPressSchechter

A dark matter halo mass bias class consistent with the halo mass function of Press and Schechter (1974) (see (Mo and White, 1996)).

darkMatterHaloBiasSheth2001

A dark matter halo mass bias class utilizing the algorithm of Sheth et al. (2001).

darkMatterHaloBiasTinker2005

A dark matter halo bias class which applies the radial dependence fitting function of (Tinker et al., 2005) to another bias class.

darkMatterHaloBiasTinker2010

A dark matter halo mass bias class utilizing the algorithm of Tinker et al. (2010). The bias is computed at the appropriate virial overdensity (see virialDensityContrast).

(Default implementation)