Constraining cosmological vorticity modes with CMB secondary anisotropies

TL;DR

This paper proposes a new method to constrain large-scale cosmic vorticity modes using CMB secondary anisotropies and galaxy surveys, providing a novel consistency test for the standard cosmological model.

Contribution

It introduces a simple estimator combining CMB and galaxy data to independently constrain vorticity modes and test for systematic biases in existing analyses.

Findings

Constraints on large-scale vorticity modes can be achieved with current data.

The method offers a new consistency check for the $\Lambda$CDM model.

Potential to detect or limit cosmic vorticity through combined CMB and galaxy observations.

Abstract

Observational searches for large-scale vorticity modes in the late time Universe are underexplored. Within the standard $\Lambda$CDM model, this is well motivated given the observed properties of the cosmic microwave background (CMB). However, this means that searches for cosmic vorticity modes can serve as a powerful consistency test of our cosmological model. We show that through combining CMB measurements of the kinetic Sunyaev-Zel'dovich and the moving lens effects with galaxy survey data we can constrain vorticity fields independently from the large scale cosmic velocity field. This approach can provide stringent constraints on the largest scale modes and can be achieved by a simple change in the standard estimators. Alternatively if one assumes there are no cosmic vorticity modes, this estimator can be used to test for systematic biases in existing analyses of kinetic Sunyaev-Zel'dovich effect in a manner analogous to curl-lensing.