Fundamental physics from future weak-lensing calibrated Sunyaev-Zel’dovich galaxy cluster counts

Abstract

Future high-resolution measurements of the cosmic microwave background (CMB) will produce catalogs of tens of thousands of galaxy clusters through the thermal Sunyaev-Zel'dovich (tSZ) effect. We forecast how well different configurations of a CMB Stage-4 experiment can constrain cosmological parameters, in particular the amplitude of structure as a function of redshift σ8(z), the sum of neutrino masses Σmν , and the dark energy equation of state w(z). A key element of this effort is calibrating the tSZ scaling relation by measuring the lensing signal around clusters. We examine how the mass calibration from future optical surveys like the Large Synoptic Survey (LSST) compares with a purely internal calibration using lensing of the CMB itself. We find that, due to its high-redshift leverage, internal calibration gives constraints on cosmological parameters comparable to the optical calibration, and can be used as a cross-check of systematics in the optical measurement. We also show that in contrast to the constraints using the CMB lensing power spectrum, lensing-calibrated tSZ cluster counts can detect a minimal Σmν at the 3-5σ level even when the dark energy equation of state is freed up.

Status of Neutrino Properties and Future Prospects—Cosmological and Astrophysical Constraints

“…This calibration can be performed through optical surveys such as LSST or through CMB lensing calibration, with comparable results. In Madhavacheril et al [139], the authors show that lensing-calibrated SZ cluster counts can provide a detection of the minimal neutrino mass m ν at > 3σ level, also in extended cosmological scenarios.…”

Improving constraints on fundamental physics parameters with the clustering of Sunyaev-Zeldovich selected galaxy clusters

“…We present forecasts for the Simons Observatory baseline and goal noise levels and forecasts for a CMB-S4-like experiment. We illustrate the constraints from clustering by comparing Fisher forecasts of the Planck primary CMB anisotropies added to SO/S4 tSZ cluster abundances Fisher matrices from [25] 1 . The cluster abundances Fisher matrices are derived from a Poisson likelihood and the clusters are binned as a function of signalto-noise, weak-lensing mass calibration, and redshift.…”

“…Here n(M, z i ) is the mass function using the functional form from [45], N (logY |logȲ , σ logY ) is a lognormal distribution of Y given the mean integrated Compton-y (Ȳ ), and the intrinsic scatter (σ logY ), the selection function is defined by the standard error function (erf) with a signalto-noise threshold 5 using the estimated error, σ N , from the matched filter (see Equation 6). The function forȲ follows the scaling relation defined in Madhavacheril et al [25],…”

“…The calibration masses M L are obtained via optical weak-lensing signals modeled by calculating the excess surface density projected along the line of sight, assuming a Navarro-Frenk-White [NFW, 56] density profile computed from the cluster mass M . The details of this procedure are elaborated further in [25].…”

Probing cosmology and cluster astrophysics with multiwavelength surveys – I. Correlation statistics

“…First, we consider the next-generation ground-based CMB experiment, referred to as CMB Stage 4 (CMB-S4; Abazajian et al 2019). Following Madhavacheril et al (2017), we adopt the experimental configuration consisting of a single large telescope with seven band-passes. Table 2 summarizes the different experimental configurations of CMB-S4 experiment setups considered in this paper.…”