Astrophysics Seminar

On the largest scales, the Universe’s matter is organized into a cosmic web, with elongated filaments intersecting at dense nodes where massive galaxy clusters form. The position of galaxies within this web is key to understanding their growth and evolution. At redshifts z > 2, the progenitors of present-day massive clusters—known as protoclusters—are thought to significantly influence the galaxies they contain, shaping trends observed in the local Universe. However, as redshift increases, tracing the large-scale structure becomes more challenging, hindering detailed, statistically robust studies of galaxy-environment relationships at early epochs.

I present results from the One-hundred-deg^2 DECam Imaging in Narrowbands (ODIN) survey, the largest deep narrowband survey to date. ODIN aims to identify statistical samples of protoclusters and cosmic filaments at z=2.4, 3.1, and 4.5, using Lyman-alpha emitting galaxies (LAEs) as tracers. The identified structures are in excellent agreement with simulations and the hierarchical model of structure formation. The large sample size of the ODIN protoclusters allows us to estimate their halo bias and halo mass through measurement of the two-point correlation function. This analysis demonstrates that the ODIN structures exhibit high biases and likely represent massive halos that could evolve into clusters similar to Coma or Virgo by z=0. Spectroscopic follow-up has confirmed many of these structures and provided insights into their three-dimensional morphology, validating the protocluster and filament samples identified by ODIN.