Program: GS-2022B-Q-214

We propose Gemini/GMOS-S spectroscopic observations of five Sunyaev-Zeldovich(SZ)-selected galaxy cluster candidates at 0.3<z<0.6 to measure their redshifts and velocity dispersions. We will use the redshifts of galaxies in the fields of cluster candidates to examine the overdensity in redshift space for cluster identification. We plan to obtain >10 member galaxies for each cluster to derive a cluster redshift and its velocity dispersion, a proxy for the dynamical mass of the cluster. The target cluster candidates are drawn from a sample of 450 cluster candidates from the Planck SZ survey, which needs to be validated whether they are genuine clusters along with their dynamical parameters. This semester, we will use this program to test the feasibility of the long-term survey for validating and measuring the cluster candidates and to prepare a proper observing strategy. Combining the sample from the future long-term survey with 1203 clusters from the same SZ survey that were already validated in previous studies will provide a complete sample of SZ-selected all-sky galaxy clusters. Gemini observation will give a chance to acquire a valuable input for the study of galaxy clusters, which is one of the legacy science cases of the upcoming SPHEREx all-sky survey.