OccupationComponent

class halotools.empirical_models.OccupationComponent(**kwargs)

Bases: object

Abstract base class of any occupation model. Functionality is mostly trivial. The sole purpose of the base class is to standardize the attributes and methods required of any HOD-style model for halo occupation statistics.

Parameters:

gal_typestring, keyword argument

Name of the galaxy population whose occupation statistics is being modeled.

thresholdfloat, keyword argument

Threshold value defining the selection function of the galaxy population being modeled. Typically refers to absolute magnitude or stellar mass.

upper_occupation_boundfloat, keyword argument

Upper bound on the number of gal_type galaxies per halo. The only currently supported values are unity or infinity.

second_momentstring, optional

Method for computing the second occupation moment. For centrals, only Bernoulli is supported. For satellites, options are “poisson” and “weighted_nearest_integer”. Satellite default is “poisson”.

prim_haloprop_keystring, optional

String giving the column name of the primary halo property governing the occupation statistics of gal_type galaxies, e.g., halo_mvir.

See also

Writing your own HOD occupation component

Methods Summary

mc_occupation([seed])

Method to generate Monte Carlo realizations of the abundance of galaxies.

Methods Documentation

mc_occupation(seed=None, **kwargs)

Method to generate Monte Carlo realizations of the abundance of galaxies.

Parameters:

prim_haloproparray, optional

Array of mass-like variable upon which occupation statistics are based. If prim_haloprop is not passed, then table keyword argument must be passed.

tableobject, optional

Data table storing halo catalog. If table is not passed, then prim_haloprop keyword argument must be passed.

seedint, optional

Random number seed used to generate the Monte Carlo realization. Default is None.

Returns:

mc_abundancearray

Integer array giving the number of galaxies in each of the input table.