Forecasting the Y500 – M500 scaling relation from the NIKA2 SZ Large Program

F Kéruzoré,F Mayet,F Ruppin,M Muñoz-Echeverría,J.-F Macías-Pérez,E Artis,L Perotto

doi:10.1051/epjconf/202225700025

Abstract

One of the key elements needed to perform the cosmological exploitation of a cluster survey is the relation between the survey observable and the cluster masses. Among these observables, the integrated Compton parameter Y is a measurable quantity in Sunyaev-Zeldovich (SZ) surveys, which tightly correlates with cluster mass. The calibration of the relation between the Compton parameter Y500 and the mass M500 enclosed within radius R500 is one of the scientific goals of the NIKA2 SZ Large Program (LPSZ). We present an ongoing study to forecast the constraining power of this program, using mock simulated datasets that mimic the large program sample, selection function, and typical uncertainties on Y500 and M500. We use a Bayesian hierarchical modelling that enables taking into account a large panel of systematic effects. Our results show that the LPSZ can yield unbiased estimates of the scaling relation parameters for realistic input parameter values. The relative uncertainties on these parameters is ~ 10% for the intercept and slope of the scaling relation, and ~ 34% for its intrinsic scatter, foreshadowing precise estimates to be delivered by the LPSZ.

Highlights

The abundance of galaxy clusters in mass and redshift is tightly linked to large scale structure formation physics
One of them is to follow-up representative samples of galaxy clusters with dedicated observations, enabling individual mass measurements that can be used to study their correlation with survey observables
We present the distributions of the biases and dispersions obtained for our 5000 LPSZ-like samples in figure 2

Summary

Introduction

The abundance of galaxy clusters in mass and redshift is tightly linked to large scale structure formation physics. Cluster surveys can be used to constrain cosmological parameters, provided cluster masses can be estimated Several approaches can be considered to estimate mass-observable scaling relations. One of them is to follow-up representative samples of galaxy clusters with dedicated observations, enabling individual mass measurements that can be used to study their correlation with survey observables. The NIKA2 SZ Large Program (hereafter LPSZ, [3, 4]) consists in a highresolution SZ follow-up of ⇠ 50 galaxy clusters selected from SZ surveys. We present a study forecasting the ability of the NIKA2 LPSZ to constrain the Y − M scaling relation. The estimation of the scaling relation from these samples allows us to forecast typical biases and uncertainties in the analysis

Scaling relation modelling

Mock cluster sample generation

Regression scheme

Results

Summary and conclusions