CMB lensing beyond the power spectrum: Cosmological constraints from the one-point probability distribution function 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 σ (PDF) and 6 σ (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 Ωm-σ8 plane by ≈30 %, compared to using the power spectrum alone.
- Publication:
-
Physical Review D
- Pub Date:
- November 2016
- DOI:
- 10.1103/PhysRevD.94.103501
- arXiv:
- arXiv:1608.03169
- Bibcode:
- 2016PhRvD..94j3501L
- Keywords:
-
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 16 pages, 16 figures, 2 tables