The Atacama Cosmology Telescope: Two-Season ACTPol Lensing Power Spectrum

TL;DR

This paper presents a measurement of the CMB lensing power spectrum from two seasons of ACTPol data, consistent with Planck LCDM predictions, and provides updated constraints on cosmological parameters including neutrino mass.

Contribution

First measurement of CMB lensing power spectrum from two seasons of ACTPol data, with systematic validation and implications for cosmological parameters.

Findings

Lensing amplitude A_lens = 1.06 +/- 0.16

Constraint on sigma_8 Omega_m^0.25 = 0.643 +/- 0.054

Updated neutrino mass sum constraints

Abstract

We report a measurement of the power spectrum of cosmic microwave background (CMB) lensing from two seasons of Atacama Cosmology Telescope Polarimeter (ACTPol) CMB data. The CMB lensing power spectrum is extracted from both temperature and polarization data using quadratic estimators. We obtain results that are consistent with the expectation from the best-fit Planck LCDM model over a range of multipoles L=80-2100, with an amplitude of lensing A_lens = 1.06 +/- 0.15 (stat.) +/- 0.06 (sys.) relative to Planck. Our measurement of the CMB lensing power spectrum gives sigma_8 Omega_m^0.25 = 0.643 +/- 0.054; including baryon acoustic oscillation scale data, we constrain the amplitude of density fluctuations to be sigma_8 = 0.831 +/- 0.053. We also update constraints on the neutrino mass sum. We verify our lensing measurement with a number of null tests and systematic checks, finding no evidence of significant systematic errors. This measurement relies on a small fraction of the ACTPol data already taken; more precise lensing results can therefore be expected from the full ACTPol dataset.