Evidence of Lensing of the Cosmic Microwave Background by Dark Matter Halos

TL;DR

This paper provides evidence that the gravitational lensing of the cosmic microwave background by dark matter halos can be detected and measured, offering a new way to study dark matter distribution in large-scale structures.

Contribution

It presents the first detection of CMB lensing by dark matter halos of around 10^13 solar masses using ACTPol data, demonstrating the method's potential.

Findings

Lensing convergence maps align with simulated dark matter profiles.

Detection significance of 3.2 sigma over null hypothesis.

Potential to probe dark matter in galaxy groups and clusters.

Abstract

We present evidence of the gravitational lensing of the cosmic microwave background by $10^{13}$ solar mass dark matter halos. Lensing convergence maps from the Atacama Cosmology Telescope Polarimeter (ACTPol) are stacked at the positions of around 12,000 optically-selected CMASS galaxies from the SDSS-III/BOSS survey. The mean lensing signal is consistent with simulated dark matter halo profiles, and is favored over a null signal at 3.2 sigma significance. This result demonstrates the potential of microwave background lensing to probe the dark matter distribution in galaxy group and galaxy cluster halos.