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

Abstract

We present a measurement of the cosmic microwave background (CMB) 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 CMB temperature and polarization maps. We report measurements of the lensing potential power spectrum in the multipole range of 100 < L < 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 ΛCDM model to the Planck 2015 TT+lowP+lensing dataset. For the minimumvariance estimator, we find A MV = 0.944 ± 0.058 (Stat.) ± 0.025 (Sys.); restricting to only polarization data, we find A POL = 0.906 ± 0.090 (Stat.) ± 0.040 (Sys.). 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. †

CMB lensing reconstruction biases in cross-correlation with large-scale structure probes

“…At lower redshift the post-Born signal decreases due to the decreased path length and the large-scale structure bispectrum grows, so there is relatively less cancellation. However, the fractional bias decreases at very low redshift due to suppression by the CMB lensing window function, so the bias remains relatively small ( 10%) for all redshifts, 13 For both these figures we did not show the residual for the SO EB estimator since simulation results are noisy and consistent with no N and therefore does not need to be modelled to high precision.…”

“…The current generation of ground-based experiments (POLARBEAR, ACTpol, SPTpol) produced the first measurements of B-modes [5][6][7] and managed to isolate CMB polarization lensing with good statistical significance [8][9][10][11][12]. The latest SPTpol measurements [13] for the first time produced CMB lensing maps from CMB polarization data with less noise than those using temperature data. Next generation experiments such as CMB-S4 and Simons Observatory [14,15] will improve the quality of CMB lensing maps dramatically, from both higher-resolution temperature data and highersensitivity polarization.…”

A Measurement of the CMB E-mode Angular Power Spectrum at Subdegree Scales from 670 Square Degrees of POLARBEAR Data

“…We also consider what impact data besides the primary CMB power spectra have on the cosmological constraints. Here we include the lensing power spectra from Planck and SPTpol (Planck Collaboration et al 2018a;Wu et al 2019). We also include the Riess et al (2019) local measurement of the Hubble constant, H 0 = 74.03 ± 1.42 km/s/Mpc.…”

“…A measurement of the B-mode power spectrum on large angular scales on this field was presented by Polarbear Collaboration et al (2019, hereafter PB19), which overlaps this work in the narrow range of angular scales 500 ≤ ≤ 600. We combine the Polarbear bandpowers with other recent CMB power spectrum measurements (Planck Collaboration et al 2019;Louis et al 2017;Story et al 2013) as well as CMB lensing power spectrum measurements (Planck Collaboration et al 2018a;Wu et al 2019), baryon acoustic oscillation (BAO) results (Beutler et al 2011;Ross et al 2015;Alam et al 2017) and Hubble constant measurements (Riess et al 2019) to study the implications for cosmology. This is the first time the cosmological implications of this combined dataset have been presented.…”

A chemically etched corrugated feedhorn array for D-band CMB observations

“…The BICEP2/Keck, POLARBEAR and, more recently, the South Pole Telescope (SPT) teams have measured the lensing B-modes power spectrum [3][4][5], allowing them to determine the dark matter lensing potential with unprecedented precision. The large-scale B-modes from primordial gravitational waves, instead, have not been detected yet.…”