PS

class hmf.mass_function.fitting_functions.PS(nu2: ndarray, m: None | ndarray = None, z: float = 0.0, n_eff: None | ndarray = None, mass_definition: None | BaseMassDefinition = None, cosmo: FLRW = FlatLambdaCDM(name='Planck15', H0=<Quantity 67.74 km / (Mpc s)>, Om0=0.3075, Tcmb0=<Quantity 2.7255 K>, Neff=3.046, m_nu=<Quantity [0., 0., 0.06] eV>, Ob0=0.0486), delta_c: float = 1.68647, **model_parameters)[source]

Press-Schechter mass function fit.

For details on attributes, see documentation for FittingFunction.

Parameters:

  • nu2 (array_like) – A vector of peak-heights, \(\delta_c^2/\sigma^2\) corresponding to m

  • m (array_like, optional) – A vector of halo masses [units M_sun/h]. Only necessary if req_mass is True. Typically provides limits of applicability. Must correspond to nu2.

  • z (float, optional) – The redshift. Only required if req_z is True, in which case the default is 0.

  • n_eff (array_like, optional) – The effective spectral index at m. Only required if req_neff is True.

  • mass_definition (hmf.halos.mass_definitions.MassDefinition instance) – A halo mass definition. Only required for fits which explicitly include a parameterization for halo definition.

  • cosmo (astropy.cosmology.FLRW instance, optional) – A cosmology. Default is Planck15. Either omegam_z or cosmo is required if req_omz is True. If both are passed, omegam_z takes precedence.

  • **model_parameters (unpacked-dictionary) – These parameters are model-specific. For any model, list the available parameters (and their defaults) using <model>._defaults

Notes

The Press-Schechter [1] form is:

\[f_{\rm PS}(\sigma) = \sqrt{\frac{2}{\pi}}\nu\exp(-0.5\nu^2)\]

References

[1]

Press, W. H., Schechter, P., 1974. ApJ 187, 425-438. http://adsabs.harvard.edu/full/1974ApJ…187..425P

Attributes

Methods

__init__(nu2: ndarray, m: None | ndarray = None, z: float = 0.0, n_eff: None | ndarray = None, mass_definition: None | BaseMassDefinition = None, cosmo: FLRW = FlatLambdaCDM(name='Planck15', H0=<Quantity 67.74 km / (Mpc s)>, Om0=0.3075, Tcmb0=<Quantity 2.7255 K>, Neff=3.046, m_nu=<Quantity [0., 0., 0.06] eV>, Ob0=0.0486), delta_c: float = 1.68647, **model_parameters)
classmethod get_measured_mdef()

Get the mass definition used in the defining simulation.

classmethod get_models() → dict[str, type]

Get a dictionary of all implemented models for this component.