class halotools.empirical_models.OccupationComponent(**kwargs)[source] [edit on github]

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.

gal_type : string, keyword argument

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

threshold : float, keyword argument

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

upper_occupation_bound : float, keyword argument

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

second_moment : string, 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_key : string, optional

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

Methods Summary

mc_occupation([seed]) Method to generate Monte Carlo realizations of the abundance of galaxies.

Methods Documentation

mc_occupation(seed=None, **kwargs)[source] [edit on github]

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

prim_haloprop : array, 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.

table : object, optional

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

seed : int, optional

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

mc_abundance : array

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