Quantifying the Colour-Dependent Stochasticity of Large-Scale Structure

TL;DR

This study investigates whether red and blue galaxies at z~0.6 trace the same large-scale structure by measuring their clustering and stochasticity, finding high correlation and minimal stochasticity between the two galaxy populations.

Contribution

It provides the first quantitative analysis of the colour-dependent stochasticity of large-scale structure at intermediate scales using SDSS data.

Findings

Correlation coefficient r > 0.95 on intermediate scales

Red and blue galaxies are highly correlated in their large-scale clustering

Minimal stochasticity between red and blue galaxy distributions

Abstract

We address the question of whether massive red and blue galaxies trace the same large-scale structure at z~0.6 using the CMASS sample of galaxies from Data Release 12 of the Sloan Digital Sky Survey III. After splitting the catalog into subsamples of red and blue galaxies using a simple colour cut, we measure the clustering of both subsamples and construct the correlation coefficient, r, using two statistics. The correlation coefficient quantifies the stochasticity between the two subsamples, which we examine over intermediate scales (20 < R < 100 Mpc/h). We find that on these intermediate scales, the correlation coefficient is consistent with 1; in particular, we find r > 0.95 taking into account both statistics and r > 0.974 using the favored statistic.