Looking for Massive Galaxy Clusters in the Early Universe

Identifying galaxy clusters and proto-clusters in the early universe is vital to better understand how galaxies grow and evolve to form large-scale structures. Collecting spectroscopic data of galaxies to find strong emission lines is a well-established method to identify these structures. Using the vast collection of spectra from the Hobby Eberly Telescope Dark Energy Experiment (HETDEX) Survey, we searched for galaxy clusters and proto-clusters at 1.9 < z < 3.5. We identified 10 potential galaxy clusters by looking for overdensities of Lyα emitters (LAE). Measuring and plotting the velocity dispersion profiles of each cluster let us estimate the clusters’ masses and found their masses to range from 1.0 × 10¹⁵ M_⊙ to 3.0 × 10¹⁵ M_⊙. Furthermore, we have discovered a potential proto-cluster candidate at z = 2.305 with 104 LAEs within a 10-arcminute radius. We identified 4 sources within the 10-arcminute radius to have broad Carbon-4 (C IV) emission lines indicating this large-scale structure contains 4 Active Galactic Nuclei (AGN). With HETDEX being an ongoing survey, we expect to find hundreds more galaxy clusters and proto-cluster candidates within the 8.5 Gpc³ of surveyed space.