Date:
Tue, 28/11/201712:30-13:30
Simulating Intergalactic Filaments: Inner Structures before the Halo Entry at z~2
As major channels of mass acquisition by galactic halos at redshifts higher than ~1, intergalactic filaments (IGFs) play a key role in the physics of gas around and in the galaxies. While identified in simulations as cold flows possibly surviving the entry in the so-called virial sphere, their actual detailed structure remains unclear. Using an AMR code (Ramses), we ran a zoom-in simulation in a cosmological context, centered on a ~3.10^11 M_sun halo at z=2.1, and selected an accreting filament to study the thermo- and hydrodynamic properties of its gaseous component. Not only have we found that the strong anisotropy of its environment would dynamically affect the condensation of a core close to its axis, precursor of the cold flow, but we can also suggest a mechanism giving rise to a virial shock at the halo entry. Moreover, we serendipitously discovered that dense, localized structures had formed along the filament, like beads on a string, whose study hint at reassessing the importance of IGFs as conveyors of globular clusters or even dwarf galaxies. Finally, we inferred from our data that gaseous filaments were likely to be turbulent and multiphase long before entering the halo, which would widely alter its envisioned interaction with the halo gas, and thus its evolution before it may eventually reach the galaxy.
As major channels of mass acquisition by galactic halos at redshifts higher than ~1, intergalactic filaments (IGFs) play a key role in the physics of gas around and in the galaxies. While identified in simulations as cold flows possibly surviving the entry in the so-called virial sphere, their actual detailed structure remains unclear. Using an AMR code (Ramses), we ran a zoom-in simulation in a cosmological context, centered on a ~3.10^11 M_sun halo at z=2.1, and selected an accreting filament to study the thermo- and hydrodynamic properties of its gaseous component. Not only have we found that the strong anisotropy of its environment would dynamically affect the condensation of a core close to its axis, precursor of the cold flow, but we can also suggest a mechanism giving rise to a virial shock at the halo entry. Moreover, we serendipitously discovered that dense, localized structures had formed along the filament, like beads on a string, whose study hint at reassessing the importance of IGFs as conveyors of globular clusters or even dwarf galaxies. Finally, we inferred from our data that gaseous filaments were likely to be turbulent and multiphase long before entering the halo, which would widely alter its envisioned interaction with the halo gas, and thus its evolution before it may eventually reach the galaxy.