Constraining ultra large-scale cosmology with multiple tracers in optical and radio surveys

TL;DR

This paper explores how combining multiple tracers from optical and radio surveys can enhance the detection of relativistic effects, primordial non-Gaussianity, and lensing magnification in large-scale cosmology.

Contribution

It introduces an optimal method for combining diverse tracers to improve measurements of large-scale cosmological effects and forecasts their detectability with upcoming surveys.

Findings

Optimal tracer combination enhances detection significance.

Forecasts show promising detection prospects with DES, LSST, and SKA.

Identifies observational challenges for future measurements.

Abstract

Multiple tracers of the cosmic density field, with different bias, number and luminosity evolution, can be used to measure the large-scale properties of the Universe. We show how an optimal combination of tracers can be used to detect general-relativistic effects in the observed density of sources. We forecast for the detectability of these effects, as well as measurements of primordial non-Gaussianity and large-scale lensing magnification with current and upcoming large-scale structure experiments. In particular we quantify the significance of these detections in the short term with experiments such as the Dark Energy Survey (DES), and in the long term with the Large Synoptic Survey Telescope (LSST) and the Square Kilometre Array (SKA). We review the main observational challenges that must be overcome to carry out these measurements.