S21A0013

The existence and ages of massive (quiescent) galaxies at high redshifts will put strong constraints on galaxy formation theories, as there would be little cosmic time available for such matured systems to develop by the observed epoch. We will conduct such an experiment at z∼5 for the first time using our unique, purpose-made medium-band filters K₁, K₂, and K₃ on SWIMS. As a pilot program, we will target 10 known proto-cluster candidates at z∼5 selected as highest over-densities (>4.5σ) of r-dropout LBGs in the HSC-SSP D/UD fields. By targeting those most overdense regions where galaxies are expected to form and grow earlier and faster in a biased manner, we can maximize the probability of our first discovery of at least a few massive monsters with M_*>6×10¹⁰M_⊙ at z∼5. Comparing this pilot proto-cluster survey with the companion general field survey, we will also quantify the bias/acceleration of galaxy formation in overdense regions in the early Universe. Those massive galaxy candidates thus discovered will strongly motivate spectroscopic follow-up observations with ≥8–10m telescopes and JWST to characterize their properties such as accurate stellar masses and ages. These will put strong constraints on the initial onset of star formation beyond the reionization epoch.

This document was translated from L^AT_EX by H^EV^EA.