The Atacama Cosmology Telescope: Temperature and Gravitational Lensing Power Spectrum Measurements from Three Seasons of Data

TL;DR

This paper reports precise measurements of the cosmic microwave background temperature and gravitational lensing power spectra from three seasons of Atacama Cosmology Telescope data, testing cosmological models and foreground effects.

Contribution

First detailed measurement of CMB temperature and lensing power spectra from ACT three-season data, including cross-frequency analysis and systematic error assessments.

Findings

Detection of higher-order peaks consistent with Lambda CDM

Measurement of CMB gravitational lensing convergence at 4.6-sigma

Constraints on Sunyaev-Zel'dovich effects and extragalactic foregrounds

Abstract

We present the temperature power spectra of the cosmic microwave background (CMB) derived from the three seasons of data from the Atacama Cosmology Telescope (ACT) at 148 GHz and 218 GHz, as well as the cross-frequency spectrum between the two channels. We detect and correct for contamination due to the Galactic cirrus in our equatorial maps. We present the results of a number of tests for possible systematic error and conclude that any effects are not significant compared to the statistical errors we quote. Where they overlap, we cross-correlate the ACT and the South Pole Telescope (SPT) maps and show they are consistent. The measurements of higher-order peaks in the CMB power spectrum provide an additional test of the Lambda CDM cosmological model, and help constrain extensions beyond the standard model. The small angular scale power spectrum also provides constraining power on the Sunyaev-Zel'dovich effects and extragalactic foregrounds. We also present a measurement of the CMB gravitational lensing convergence power spectrum at 4.6-sigma detection significance.