Halo Occupation Distribution Modeling of Green Valley Galaxies

TL;DR

This study analyzes the clustering of green valley galaxies using a novel multi-tracer halo occupation distribution method, revealing their intermediate halo properties and satellite fractions compared to red and blue galaxies.

Contribution

Introduces a new multi-tracer analysis technique for modeling galaxy clustering and halo occupation, improving accuracy for sparse galaxy populations.

Findings

Green valley galaxies have intermediate halo masses.

Red galaxies are more likely to be satellites in massive halos.

The satellite fraction of green galaxies is between blue and red galaxies.

Abstract

We present a clustering analysis of near ultraviolet (NUV) - optical color selected luminosity bin samples of green valley galaxies. These galaxy samples are constructed by matching the Sloan Digital Sky Survey Data Release 7 with the latest Galaxy Evolution Explorer source catalog which provides NUV photometry. We present cross-correlation function measurements and determine the halo occupation distribution of these transitional galaxies using a new multiple tracer analysis technique. We extend the halo-occupation formalism to model the cross-correlation function between a galaxy sample of interest and multiple tracer populations simultaneously. This method can be applied to commonly used luminosity threshold samples as well as to color and luminosity bin selected galaxy samples, and improves the accuracy of clustering analyses for sparse galaxy populations. We confirm the previously observed trend that red galaxies reside in more massive halos and are more likely to be satellite galaxies than average galaxies of similar luminosity. While the change in central galaxy host mass as a function of color is only weakly constrained, the satellite fraction and characteristic halo masses of green satellite galaxies are found to be intermediate between those of blue and red satellite galaxies.