Large-scale structure in the local Universe with the S-PLUS survey

Abstract

The main goal of the present generation of extragalactic surveys (e.g., eBOSS and DES) is the exploration of cosmological parameters, in particular the equation of state of dark energy. However, there is now an increasing realization of the subtle interplay between between cosmology, large-scale structure, and galaxy evolution. Issues such as the bias of galaxies and halos, the pattern of redshift-space distortions (both in the linear and non-linear regimes), and how galaxies occupy different halos, are all key to exploring both the cosmological potential of new datasets, as well as to solving some long-standing issues in galaxy evolution. The existing theoretical framework of the Halo Model, along with the HODs (halo occupation distributions), allow us to make a simple but powerful description of large-scale structure that spans the largest distances as well as the intra-halo matter distribution. Recently we have developed new statistical techniques for analyzing galaxy maps with different tracers of large-scale structure. This technique has been used successfully in the study of cosmological effects on very large scales, but it is also a powerful tool for the simultaneous study of both cosmological and astrophysical aspects. With this project we will extend the range of applications of this toolset. First, we will calibrate the suite of codes using the MultiDARK N-body simulations, studying also how halo bias depends on environmental parameters such as the age of the halos, their concentration, spin, as well as other potential secondary bias parameters. In a second step, we will use our techniques to analyze the data from the S-PLUS main survey -- a new galaxy catalog that is being produced with data from the T80-South telescope. With this new dataset we will measure the clustering of galaxies according to their type, luminosity, stellar mass and other indicators of their environment. The results will be used for a range of applications: (a) measuring the scale of acoustic oscillations at low redshifts, imposing constraints on the dark energy equation of state; (b) measuring the pattern of redshift-space distortions and the matter growth rate, which will allow us to study how General Relativity is (or isn't) suited to describe gravity on the largest scales; (c) the influence of secondary bias parameters (other than the primary parameter, which is halo mass) on the bias of galaxies at low redshifts; and (d) to determine the halo occupation distribution of the different galaxy types in the local Universe. Finally, this project will also help with the operations of the T80-South, with a technical training (TT) fellowship and the CTIO internet fee for the T80-South for the year 2018. (AU)