A Measurement of the Cosmic Microwave Background Lensing Potential and Power Spectrum from 500 deg² of SPTpol Temperature and Polarization Data

Abstract

Abstract We present a measurement of the cosmic microwave background lensing potential using 500 deg 2 of 150 GHz data from the SPTpol receiver on the South Pole Telescope. The lensing potential is reconstructed with signal-to-noise per mode greater than unity at lensing multipoles L ≲ 250, using a quadratic estimator on a combination of cosmic microwave background temperature and polarization maps. We report measurements of the lensing potential power spectrum in the multipole range of 100 &lt; L &lt; 2000 from sets of temperature-only ( T ), polarization-only (POL), and minimum-variance (MV) estimators. We measure the lensing amplitude by taking the ratio of the measured spectrum to the expected spectrum from the best-fit Λ cold dark matter model to the Planck 2015 TT + low P + lensing data set. For the minimum-variance estimator, we find <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>A</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>MV</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0.944</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.058</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mi>Stat</mml:mi> <mml:mi>.</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mo>±</mml:mo> <mml:mn>0.025</mml:mn> <mml:mspace width="0.33em"/> <mml:mo stretchy="false">(</mml:mo> <mml:mi>Sys</mml:mi> <mml:mi>.</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mo>;</mml:mo> </mml:math> restricting to only polarization data, we find <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>A</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>POL</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0.906</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.090</mml:mn> <mml:mspace width="0.33em"/> <mml:mo stretchy="false">(</mml:mo> <mml:mi>Stat</mml:mi> <mml:mi>.</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mo>±</mml:mo> <mml:mn>0.040</mml:mn> <mml:mspace width="0.33em"/> <mml:mo stretchy="false">(</mml:mo> <mml:mi>Sys</mml:mi> <mml:mi>.</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:math> . Considering statistical uncertainties alone, this is the most precise polarization-only lensing amplitude constraint to date (10.1 σ ) and is more precise than our temperature-only constraint. We perform null tests and consistency checks and find no evidence for significant contamination.