Dynamical Properties and Velocity Dispersion-Mass Relation of $z \sim 1$ Galaxy Clusters from the GOGREEN and GCLASS Surveys

TL;DR

This study analyzes galaxy clusters at redshift around 1, establishing a reliable velocity dispersion-mass relation using a novel membership technique, confirming its consistency with simulations and its utility for mass estimation.

Contribution

Introduces and validates the GalWeight technique for cluster membership, demonstrating its effectiveness in deriving dynamical properties and confirming the velocity dispersion-mass relation at high redshift.

Findings

Velocity dispersion-mass relation consistent with cosmological simulations.

GalWeight technique effectively assigns cluster membership.

Velocity dispersion can directly estimate cluster mass.

Abstract

We investigate a sample of 14 galaxy clusters from the GOGREEN and GCLASS (GG) spectroscopic datasets within the redshift range $(0.87 \leq z \leq 1.37)$ and cluster masses $\mathrm{M}_{200} \gtrsim 2\times 10^{14}$ \hm. Using the highly effective GalWeight technique for cluster membership assignment developed by our own team, we derive the dynamical parameters of these clusters through the virial mass estimator. We examine the velocity dispersion-cluster mass relation $(\sigma \mathrm{MR})$ for the GG cluster sample. We find, $\log{\sigma_{200}} = (2.94\pm0.02) + (0.37\pm0.07)\log{\mathrm{M}_{200}}$ with an intrinsic scatter of $(\sigma_\mathrm{int} = 0.02 \pm 0.02)$. Our results demonstrate that the $(\sigma \mathrm{MR})$ relation is consistent with predictions from cosmological simulations, highlighting the reliability of the GalWeight technique for cluster membership assignment. Furthermore, the $(\sigma \mathrm{MR})$ validates the robustness of the virial mass estimator in accurately recovering cluster masses and associated parameters. Importantly, our findings confirm that velocity dispersion can be used directly to estimate cluster mass without relying on dynamical mass estimators.