Calibrating Cluster Number Counts with CMB lensing

TL;DR

This paper demonstrates how combining CMB lensing and SZ cluster data from future experiments can precisely calibrate cluster masses, constrain cosmological parameters, and potentially detect the neutrino mass sum.

Contribution

It introduces a method to internally calibrate cluster masses using high signal-to-noise CMB lensing data from Stage-4 experiments, improving cosmological constraints.

Findings

CMB Stage-4 will constrain hydrostatic bias to sub-percent accuracy.

The joint analysis could detect the lower limit of neutrino mass sum at about 5 sigma.

Constraints on the non-parametric Y-M relationship can inform its evolution with mass and redshift.

Abstract

CMB Stage-4 experiments will reduce the uncertainties on the gravitational lensing potential by an order of magnitude compared to current measurements, and will also produce a Sunyaev-Zel'dovich (SZ) cluster catalog containing $\sim10^{5}$ objects, two orders of magnitudes higher than what is currently available. In this paper we propose to combine these two observables and show that it is possible to calibrate the masses of the full Stage-4 cluster catalog internally owing to the high signal to noise measurement of the CMB lensing convergence field. We find that a CMB Stage-4 experiment will constrain the hydrostatic bias parameter to sub-percent accuracy. We also show constraints on a non parametric $Y-M$ relationship which could be used to study its evolution with mass and redshift. Finally we present a joint likelihood for thermal SZ (tSZ) flux and mass measurements, and show that it could lead to a $\sim5\sigma$ detection of the lower limit on the sum of the neutrino masses in the normal hierarchy ($\sum m_{\nu}=60 \textrm{meV}$) once combined with measurements of the primordial CMB and CMB lensing power spectra.