Cosmology through correlations

点击翻译按钮获取中文摘要

Thanks to data gathered with innovative instrumentation, we now have the answers to some of the most fundamental questions in cosmology.  A relatively simple 6-parameter model describes the structure and evolution of the Universe on the largest scales; on smaller scales, the growth of dark matter halos, which host galaxies and galaxy clusters, is also well understood. The Planck satellite has set the gold-standard for estimating cosmological parameters; it is now wrapping up its analysis, which has confirmed the standard paradigm developed in the last 20 years or so. So where does cosmology go from here? We still need to determine WHY the Universe is the way it is, in terms of fundamental forces, i.e. where the basic cosmological model came from, how the model might still be incomplete, and how it relates to high-energy physics theories. Secondly, the formation and evolution of galaxies within dark matter halos is shrouded in complexity, so that we don't really know HOW the basic building blocks of the Universe form and evolve. To make progress in these two directions, we must dig deeper into cosmological studies. A set of inter-related tools utilises correlations to tease out additional information from large surveys. This includes careful investigations of one-point (so-called "P(D)") and two-point (i.e. power spectra) statistics of deep extragalactic data sets covering a wide range of wavelengths. Additionally, correlations between the cosmic microwave background and other tracers of structure offer powerful avenues for constraining cosmological models - the cosmic infrared and radio backgrounds, gravitational lensing, galaxy clustering and scattering effects in galaxy clusters. It is through these correlation studies that cosmology will advance towards direct connection with underlying physics - both to reveal the relationship between the standard cosmological model and underlying physical theories, and to understand how complex baryonic physics shapes the properties of galaxies within dark matter potentials.**