First measurement of gravitational lensing by cosmic voids in SDSS

TL;DR

This study presents the first detection of gravitational lensing effects caused by cosmic voids, using SDSS data, revealing a depression in lensing signal at void radii consistent with theoretical models.

Contribution

It provides the first measurement of lensing by cosmic voids through stacking SDSS data, confirming theoretical predictions of matter underdensity effects.

Findings

Detected a significant lensing depression at void radii

Results agree with analytical models of void matter profiles

Data and code are publicly available for further research

Abstract

We report the first measurement of the diminutive lensing signal arising from matter underdensities associated with cosmic voids. While undetectable individually, by stacking the weak gravitational shear estimates around 901 voids detected in SDSS DR7 by Sutter et al. (2012a), we find substantial evidence for a depression of the lensing signal compared to the cosmic mean. This depression is most pronounced at the void radius, in agreement with analytical models of void matter profiles. Even with the largest void sample and imaging survey available today, we cannot put useful constraints on the radial dark-matter void profile. We invite independent investigations of our findings by releasing data and analysis code to the public at https://github.com/pmelchior/void-lensing