Autocorrelations of stellar light and mass at z~0 and ~1: From SDSS to DEEP2

TL;DR

This study measures how stellar mass and light from galaxies cluster at redshifts around 0 and 1, revealing environmental effects on stellar populations and testing galaxy formation models against observations.

Contribution

It provides the first detailed comparison of galaxy autocorrelations in stellar mass and light at two redshifts, and evaluates the accuracy of Millennium Simulation predictions.

Findings

Clustering patterns are similar at z~0 and z~1.

The Millennium Simulation reproduces luminosity clustering within 30%.

Mass autocorrelations are overpredicted below 2 Mpc.

Abstract

We present measurements of projected autocorrelation functions w_p(r_p) for the stellar mass of galaxies and for their light in the U, B and V bands, using data from the third data release of the DEEP2 Galaxy Redshift Survey and the final data release of the Sloan Digital Sky Survey (SDSS). We investigate the clustering bias of stellar mass and light by comparing these to projected autocorrelations of dark matter estimated from the Millennium Simulations (MS) at z=1 and 0.07, the median redshifts of our galaxy samples. All of the autocorrelation and bias functions show systematic trends with spatial scale and waveband which are impressively similar at the two redshifts. This shows that the well-established environmental dependence of stellar populations in the local Universe is already in place at z=1. The recent MS-based galaxy formation simulation of Guo et al. (2011) reproduces the scale-dependent clustering of luminosity to an accuracy better than 30% in all bands and at both redshifts, but substantially overpredicts mass autocorrelations at separations below about 2 Mpc. Further comparison of the shapes of our stellar mass bias functions with those predicted by the model suggests that both the SDSS and DEEP2 data prefer a fluctuation amplitude of sigma_8 0.8 rather than the sigma_8=0.9 assumed by the MS.