HOD_Model¶

class halotools.halo_occupation.HOD_Model(parameter_dict=None, threshold=None)[source] [edit on github]¶

Bases: object

Base class for any HOD-style model of the galaxy-halo connection.

This is an abstract class, so you can’t instantiate it. Instead, you must work with one of its concrete subclasses, such as Zheng07_HOD_Model or vdB03_Quenching_Model.

All HOD-style models must provide their own specific functional forms for how $\langle N_{cen} \rangle$ and $\langle N_{sat}\rangle$ vary with the primary halo property. Additionally, any HOD-based mock must specify the assumed concentration-halo relation.

Notes

Currently, the only baseline HOD model that has been implemented is based on Zheng et al. 2007, which is specified in terms of virial halo mass. But the HOD_Model class is sufficiently general that it will support models for the galaxy-halo connection based on alternative host halo properties, such as $V_{max}$ or $M_{PE-corrected}$ .

The only radial profile implemented is NFW, but this requirement will eventually be relaxed, so that arbitrary radial profiles are supported.

Mocks instances constructed with the current form of this class only exist in configuration space. Redshift-space features coming soon.

Attributes Summary

primary_halo_property_key String providing the key to the halo catalog dictionary where the primary halo property data is stored.

Methods Summary

`mean_concentration`(primary_halo_property, ...)	Concentration-halo relation assumed by the model.
`mean_ncen`(primary_halo_property, halo_type)	Expected number of central galaxies in a halo as a function of the primary property $p$ and binary-valued halo type $h_{i}$ Required method of any HOD_Model subclass.
`mean_nsat`(primary_halo_property, halo_type)	Expected number of satellite galaxies in a halo as a function of the primary property $p$ and binary-valued halo type $h_{i}$ Required method of any HOD_Model subclass.

Attributes Documentation

primary_halo_property_key¶

String providing the key to the halo catalog dictionary where the primary halo property data is stored.

Required attribute of any HOD_Model subclass.

Methods Documentation

mean_concentration(primary_halo_property, halo_type)[source] [edit on github]¶

Concentration-halo relation assumed by the model. Used to assign positions to satellites.

Required method of any HOD_Model subclass.

mean_ncen(primary_halo_property, halo_type)[source] [edit on github]¶

Expected number of central galaxies in a halo as a function of the primary property $p$ and binary-valued halo type $h_{i}$

Required method of any HOD_Model subclass.

mean_nsat(primary_halo_property, halo_type)[source] [edit on github]¶

Expected number of satellite galaxies in a halo as a function of the primary property $p$ and binary-valued halo type $h_{i}$

Required method of any HOD_Model subclass.

Navigation

HOD_Model¶

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