A CMB lensing mass map and its correlation with the cosmic infrared background

TL;DR

This paper presents the first image of CMB lensing convergence from South Pole Telescope data and demonstrates a strong correlation with Herschel infrared maps, revealing insights into the mass distribution and dusty galaxy bias.

Contribution

It introduces the first CMB lensing convergence map with significant features and establishes a strong correlation with submillimeter galaxy maps, measuring galaxy bias factors.

Findings

First image of CMB lensing convergence with ~4 sigma significance.

Strong correlation between CMB lensing map and Herschel/SPIRE submm maps (6.7-8.8 sigma).

Estimated galaxy bias factors of 1.3-1.8 with 15% uncertainty.

Abstract

We use a temperature map of the cosmic microwave background (CMB) obtained using the South Pole Telescope at 150 GHz to construct a map of the gravitational convergence to z ~ 1100, revealing the fluctuations in the projected mass density. This map shows individual features that are significant at the ~ 4 sigma level, providing the first image of CMB lensing convergence. We cross-correlate this map with Herschel/SPIRE maps covering 90 square degrees at wavelengths of 500, 350, and 250 microns. We show that these submillimeter-wavelength (submm) maps are strongly correlated with the lensing convergence map, with detection significances in each of the three submm bands ranging from 6.7 to 8.8 sigma. We fit the measurement of the cross power spectrum assuming a simple constant bias model and infer bias factors of b=1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed model for the redshift distribution of the dusty galaxies that are contributing to the Herschel/SPIRE maps.