Cosmology with Peculiar Velocity Surveys

TL;DR

Peculiar velocity surveys measure galaxy motions caused by gravity, offering a promising way to constrain cosmological models and test gravity theories with upcoming comprehensive datasets.

Contribution

This paper reviews the physics, measurement methods, and statistical tools for peculiar velocity surveys, highlighting their potential to advance cosmological understanding.

Findings

Upcoming surveys will map the local universe's velocity field.

Peculiar velocities can constrain the growth rate of structure.

Data will inform theories of gravity and cosmology.

Abstract

Peculiar velocities are the motions of galaxies due to the gravitational influence of large-scale structure, and thus are an important cosmological probe of the underlying matter density field. In recent years the number of surveys designed to measure peculiar velocities has increased, to the point that it is plausible that we will have completely mapped out the peculiar velocity field in the local universe within the next decade. Such an abundance of data will enable us to place precise constraints on the growth rate of large-scale structure which in turn will inform us about the true nature of the laws of gravity and the standard cosmological model. In this chapter, the physics governing the generation of peculiar velocities, the methods of measuring them, and the statistical tools used to extract cosmological information from them are described. It will also cover a swathe of current and future surveys dedicated to collecting peculiar velocities, what their aims are, and what these datasets may mean for the future of cosmological analyses.