Speaker
Description
Cosmic filaments represent the sites where the majority of galaxies in the universe form. However, the structure of filaments themselves, and the link between physical properties of galaxies and their spatial distribution within the filaments remain unclear. Here based on deep multi-wavelength data in the COSMOS and SDSS surveys, we characterize projected radial profiles (2-dimension) of cosmic filaments at 0 < z < 1.2, which are traced by both the stellar mass and number densities of galaxies within the filaments. We reveal that the average slope of the radial profiles of filaments changes with the distance to the filament spine, and exhibit a minimum at ∼ 0.4 Mpc (Rmin), with no obvious
evolution with redshifts. This characteristic distance mimics the splashback radius of dark matter halos, which defines a natural boundary for cosmic filaments. Identical results are obtained in the TNG300 simulations with the same process of filaments identification applied. Moreover, we further study the density profiles of filaments in 3-dimension in simulations, yielding a larger Rmin ∼ 1Mpc compared to ∼ 0.4 Mpc seen in the 2-dimension projection. The lack of evolution of Rmin with redshifts suggests a universal density profiles of cosmic filaments, which is at least valid during the last 8 Gyrs of cosmic time.
