density_threshold

halotools.empirical_models.density_threshold(cosmology, redshift, mdef)[source] [edit on github]

The threshold density for a given spherical-overdensity mass definition.

\(\rho_{\rm thresh}(z) = \Delta_{\rm ref}(z)\rho_{\rm ref}(z)\).

See Halo Mass and Radius Definitions for details.

Parameters:

cosmology : object

Instance of an Astropy cosmology object.

redshift: array_like

Can be a scalar or a numpy array.

mdef: str

String specifying the halo mass definition, e.g., ‘vir’ or ‘200m’.

Returns:

rho: array_like

The threshold density in physical \(M_{\odot}h^2/Mpc^3\). Has the same dimensions as the input redshift.

See also

delta_vir
The virial overdensity in units of the critical density.