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Theoretical Models of the Halo Occupation Distribution: Separating Central and Satellite Galaxies

9 Pith papers cite this work. Polarity classification is still indexing.

9 Pith papers citing it
abstract

The halo occupation distribution (HOD) describes the relation between galaxies and dark matter at the level of individual dark matter halos. The properties of galaxies residing at the centers of halos differ from those of satellite galaxies because of differences in their formation histories. Using a smoothed particle hydrodynamics (SPH) simulation and a semi-analytic (SA) galaxy formation model, we examine the separate contributions of central and satellite galaxies to the HOD, more specifically to the probability P(N|M) that a halo of virial mass M contains N galaxies of a particular class. In agreement with earlier results for dark matter subhalos, we find that the mean occupation function <N> for galaxies above a baryonic mass threshold can be approximated by a step function for central galaxies plus a power law for satellites, and that the distribution of satellite numbers is close to Poisson at fixed halo mass. For galaxy samples defined by different baryonic mass thresholds, there is a nearly linear relation between the minimum halo mass Mmin required to host a central galaxy and the mass M1 at which an average halo hosts one satellite, with M1 ~ 14 Mmin (SPH) or M1 ~ 18 Mmin (SA). The mean occupation number of young galaxies exhibits a local minimum at M ~ 10 Mmin where halos are too massive to host a young central galaxy but not massive enough to host satellites. We show that the conditional galaxy mass function at fixed halo mass cannot be described by a Schechter function because central galaxies produce a "bump" at high masses. We suggest parameterizations for the HOD and the conditional luminosity function that can be used to model observed galaxy clustering. Many of our predictions are in good agreement with recent results inferred from clustering in the Sloan Digital Sky Survey.

years

2026 7 2025 2

verdicts

UNVERDICTED 9

representative citing papers

Clustering of high-redshift quasars with DESI DR2

astro-ph.CO · 2026-06-25 · unverdicted · novelty 7.0

DESI DR2 quasar sample yields bias b_Q(z=2.48)=3.61 that evolves as b(z)=0.230[(1+z)^2-6.565]+2.394, consistent with constant ~10^12 M_sun halo mass and weak luminosity dependence at fixed redshift.

Revisiting the 'Lensing is Low' Problem with UNIONS

astro-ph.CO · 2026-06-22 · unverdicted · novelty 5.0

New UNIONS galaxy-galaxy lensing data around CMASS galaxies indicates no significant lensing is low problem, with joint HOD fits to GGL and GC favoring a slightly lower matter power spectrum amplitude than Planck.

Cosmology from Clustering of Continuum Galaxies

astro-ph.CO · 2026-06-23 · unverdicted · novelty 3.0

Forecasts angular clustering for a 20,000 sq deg SKAO radio continuum survey reaching O(300-400 million) sources and discusses needed corrections for telescope systematics and population modeling.

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Showing 9 of 9 citing papers.