Galaxy cluster mass bias from projected mass maps: The Three Hundred-NIKA2 LPSZ twin samples

TL;DR

This study investigates the systematic bias in galaxy cluster mass estimates caused by modeling assumptions, using simulations to quantify the impact of projection effects and modeling choices on mass bias and scatter.

Contribution

It provides a detailed analysis of how cluster orientation, radial fitting ranges, and projection effects influence mass bias in spherical models using the Three Hundred simulations.

Findings

Projection effects introduce 10-16% uncertainties in mass estimates.

Cluster orientation and radial range significantly affect mass bias.

Scatter in mass bias across clusters is less than 9% of true mass.

Abstract

The determination of the mass of galaxy clusters from observations is subject to systematic uncertainties. Beyond the errors due to instrumental and observational systematic effects, in this work we investigate the bias introduced by modelling assumptions. In particular, we consider the reconstruction of the mass of galaxy clusters from convergence maps employing spherical mass density models. We made use of The Three Hundred simulations, selecting clusters in the same redshift and mass range as the NIKA2 Sunyaev-Zel'dovich Large Programme sample: $3 \leq M_{500}/ 10^{14} \mathrm{M}_{\odot} \leq 10$ and $0.5 \leq z \leq 0.9$. We studied different modelling and intrinsic uncertainties that should be accounted for when using the single cluster mass estimates for scaling relations. We confirm that the orientation of clusters and the radial ranges considered for the fit have an important impact on the mass bias. The effect of the projection adds uncertainties to the order of $10\%$ to $16\%$ to the mass estimates. We also find that the scatter from cluster to cluster in the mass bias when using spherical mass models is less than $9\%$ of the true mass of the clusters.