GOLDRUSH. III. A Systematic Search of Protoclusters at $z\sim4$ Based on the $>100\,\mathrm{deg^2}$ Area

Understand

We conduct a systematic search for galaxy protoclusters at $z\sim3.8$ based on the latest internal data release (S16A) of the Hyper SuprimeCam Subaru strategic program (HSC-SSP).

• In the Wide layer of the HSC-SSP, we investigate the large-scale projected sky distribution of $g$-dropout galaxies over an area of $121\,\mathrm{deg^2}$, and identify 216 large-scale overdense regions ($>4\sigma$ overdensity significance) that are good protocluster candidates.
• Of these, 37 are located within $8\,\mathrm{arcmin}$ ($3.4\,\mathrm{physicalMpc}$) from other protocluster candidates of higher overdensity, and are expected to merge into a single massive structure by $z=0$.
• Therefore, we find 179 unique protocluster candidates in our survey.