CMB Lensing Beyond the Power Spectrum: Cosmological Constraints from the One-Point PDF and Peak Counts

Abstract

Unprecedentedly precise cosmic microwave background (CMB) data are expected from ongoing and near-future CMB Stage-III and IV surveys, which will yield reconstructed CMB lensing maps with effective resolution approaching several arcminutes. The small-scale CMB lensing fluctuations receive non-negligible contributions from nonlinear structure in the late-time density field. These fluctuations are not fully characterized by traditional two-point statistics, such as the power spectrum. Here, we use $N$-body ray-tracing simulations of CMB lensing maps to examine two higher-order statistics: the lensing convergence one-point probability distribution function (PDF) and peak counts. We show that these statistics contain significant information not captured by the two-point function, and provide specific forecasts for the ongoing Stage-III Advanced Atacama Cosmology Telescope (AdvACT) experiment. Considering only the temperature-based reconstruction estimator, we forecast 9$\sigma$ (PDF) and 6$\sigma$ (peaks) detections of these statistics with AdvACT. Our simulation pipeline fully accounts for the non-Gaussianity of the lensing reconstruction noise, which is significant and cannot be neglected. Combining the power spectrum, PDF, and peak counts for AdvACT will tighten cosmological constraints in the ${\Omega }_m$-${\sigma }_8$ plane by $\approx 30\%$, compared to using the power spectrum alone.

16 pages, 16 figures, 2 tables; v2 matches PRD accepted version; note changes in forecasted SNR of non-Gaussian PDF and peak counts, other results unchanged

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Cited by in corpus (5)

• Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments
• Calibrating Cluster Number Counts with CMB lensing
• Isotropy analyses of the Planck convergence map
• An Accurate Analytic Model for the Thermal Sunyaev-Zel'dovich One-Point PDF
• CMB lensing bi-spectrum: assessing analytical predictions against full-sky lensing simulations