Ringing the universe with cosmic emptiness: void properties through a combined analysis of stacked weak gravitational and Doppler lensing

TL;DR

This paper introduces a new Doppler lensing technique to analyze cosmic voids, improving mass profile inference and combining it with weak lensing for tighter constraints on void properties, relevant for upcoming surveys.

Contribution

It develops a novel Doppler lensing method for cosmic void analysis and demonstrates its effectiveness when combined with weak lensing, enhancing understanding of void mass profiles.

Findings

Combined lensing techniques yield tighter constraints on void properties.

Better agreement between lensing-inferred and tracer-inferred density profiles.

New Doppler lensing method improves void mass profile inference.

Abstract

An essential aspect of cosmic voids is that these underdense regions provide complementary information about the properties of our Universe. Unlike dense regions, voids are avoided by matter and are less contaminated by baryonic processes. The first step to understanding the properties of cosmic voids is to correctly infer their mass profiles. In the literature, various techniques have been implemented. In this paper, we review them and implement a new technique that is based on Doppler lensing. We use a relativistic $N$-body code, \textsc{Gevolution}, to generate cosmological mass perturbations and implement a three-dimensional ray-tracing technique, which follows the evolution of a ray-bundles. We focus on the various properties of cosmic voids (e.g. void size function, 2-point correlation function, and the density profile of voids), and compare the results with their universal trends. We show that when weak-lensing is combined with the Doppler lensing we obtain even tighter constraints than weak-lensing alone. We also obtain better agreement between density profiles within central parts of voids inferred from lensing and density profiles inferred from halo tracers. The implication of the result relevant to the ongoing and prospective low-redshift spectroscopic surveys is briefly discussed.