Optimal filters for the moving lens effect

TL;DR

This paper develops optimal filters to detect the moving lens effect in the CMB, enabling high-significance measurements of cosmic structure velocities with upcoming surveys.

Contribution

It introduces a new set of optimal filters for the moving lens effect and demonstrates their effectiveness in reconstructing the transverse velocity field.

Findings

High significance detection prospects with upcoming experiments.

Good agreement with previous quadratic estimator methods.

Potential for large-scale velocity field reconstruction.

Abstract

We assess the prospects for detecting the moving lens effect using cosmological surveys. The bulk motion of cosmological structure induces a small-scale dipolar temperature anisotropy of the cosmic microwave radiation (CMB), centered around halos and oriented along the transverse velocity field. We introduce a set of optimal filters for this signal, and forecast that a high significance detection can be made with upcoming experiments. We discuss the prospects for reconstructing the bulk transverse velocity field on large scales using matched filters, finding good agreement with previous work using quadratic estimators.