The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Angular clustering tomography and its cosmological implications

TL;DR

This paper uses a tomographic galaxy clustering approach on SDSS-III BOSS data to constrain cosmological parameters, providing insights into galaxy bias evolution and testing extensions of the standard cosmological model.

Contribution

It introduces a novel tomographic analysis of galaxy clustering with full shape modeling, yielding new measurements of galaxy bias and competitive cosmological constraints.

Findings

Galaxy bias evolution measured across redshifts.

Constraints on dark energy equation of state parameter, w_DE.

Results consistent with the standard ΛCDM model.

Abstract

We investigate the cosmological implications of studying galaxy clustering using a tomographic approach applied to the final BOSS DR12 galaxy sample, including both auto- and cross-correlation functions between redshift shells. We model the signal of the full shape of the angular correlation function, $\omega(\theta)$, in redshift bins using state-of-the-art modelling of non-linearities, bias and redshift-space distortions. We present results on the redshift evolution of the linear bias of BOSS galaxies, which cannot be obtained with traditional methods for galaxy-clustering analysis. We also obtain constraints on cosmological parameters, combining this tomographic analysis with measurements of the cosmic microwave background (CMB) and type Ia supernova (SNIa). We explore a number of cosmological models, including the standard $\Lambda$CDM model and its most interesting extensions, such as deviations from $w_\rm{DE} = -1$, non-minimal neutrino masses, spatial curvature and deviations from general relativity using the growth-index $\gamma$ parametrisation. These results are, in general, comparable to the most precise present-day constraints on cosmological parameters, and show very good agreement with the standard model. In particular, combining CMB, $\omega(\theta)$ and SNIa, we find a value of $w_\rm{DE}$ consistent with $-1$ to a precision better than 5\% when it is assumed to be constant in time, and better than 6\% when we also allow for a spatially-curved Universe.