Searching for the most distant Planck-selected proto-cluster using Subaru Hyper Suprime-Cam data

The released data of the wide-deep field survey in visible light with the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) has discovered galaxy clusters that are about 11 to 13.8 billion years old that have the redshift z = 4~6 (Aihara et al. 2022). Observations of galaxies over most of the 13.8 billion years of history of the universe have led to a broad-brush understanding of the basics of galaxy evolution. However, observations of distant galaxies in visible light are limited because they are strongly affected by the attenuation caused by dust. Taking advantage of the Planck full-sky survey in sub-millimeter, it is possible to see proto-clusters of galaxies buried in the dust in the Planck beam area. This research aims to identify proto-clusters of dusty-buried galaxies in the early universe using the HSC-SSP and Planck data. The Planck full-sky survey in sub-millimeter has identified more than 2,000 Planck High-z sources (PHz sources) (Ade et al. 2016). The HSC wide-deep field of view will overcome the problem of insufficient statistics of PHz sources in the Planck beam area. By using the Subaru HSC high-sensitivity and wide-deep field data, I examine the spatial distribution of the Lyman Break Galaxies (LBGs) and identify proto-cluster candidates in over-densities from Planck-selected using the Lyman Break Technique. This study focuses on five optical multicolor band filters (g, r, i, z, and y) to systematically search and identify the most distant Planck-selected proto-clusters at z = 4~5. The large number of proto-cluster candidates obtained from this study will lead to the determination of whether the proto-cluster exists in the formation process, especially in distant regions where the density is large. This study contributes to understanding the formation of the structure of the universe and the evolution of galaxies.