2025ApJ...994..205A

We investigate a sample of 14 galaxy clusters from the GOGREEN and GCLASS (GG) spectroscopic data sets within the redshift range 0.87 ≤ z ≤ 1.37 and cluster masses M₂₀₀ ≳ 2 × 10¹⁴h^–1M_⊙. 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 (σMR) for the GG cluster sample. We find ${\mathrm{log}}{\sigma }_{200}=(2.94\,\pm \,0.02)+(0.37\,\pm \,0.09){\mathrm{log}}{M}_{200}$ with an intrinsic scatter of σ_int = 0.02 ± 0.02. Our results demonstrate that the σMR relation is consistent with predictions from cosmological simulations, highlighting the reliability of the GalWeight technique for cluster membership assignment. Furthermore, the σMR 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.