Related papers: Efficiency of gas cooling and accretion at the dis…
For most of their lives, galaxies are surrounded by large and massive coronae of hot gas, which constitute vast reservoirs for gas accretion. This Chapter describes a mechanism that allows star-forming disc galaxies to extract gas from…
Star-forming galaxies like the Milky Way are surrounded by a hot gaseous halo at the virial temperature - the so-called galactic corona - that plays a fundamental role in their evolution. The interaction between the disc and the corona has…
Star formation in most galaxies requires cosmic gas accretion because the gas consumption time is short compared to the Hubble time. This accretion presumably comes from a combination of infalling satellite debris, cold flows, and…
We present evidence for cosmological gas accretion onto spiral galaxies in the local universe. The accretion is seen through its effects on the dynamics of the extra-planar neutral gas. The accretion rates that we estimate for two nearby…
Accretion of fresh gas at a rate of ~ 1 M_{sun} yr^{-1} is necessary in star-forming disc galaxies, such as the Milky Way, in order to sustain their star-formation rates. In this work we present the results of a new hydrodynamic simulation…
We use a suite a cooling halo simulations to study a new mechanism for rapid accretion of hot halo gas onto star-forming galaxies. Correlated supernovae events create converging 'superbubbles' in the halo gas. Where these collide, the…
In galaxies like the Milky Way, cold (~ 10^4 K) gas ejected from the disc by stellar activity (the so-called galactic-fountain gas) is expected to interact with the virial-temperature (~ 10^6 K) gas of the corona. The associated transfer of…
Star-forming disc galaxies such as the Milky Way need to accrete $\gsim$ 1 $M_{\odot}$ of gas each year to sustain their star formation. This gas accretion is likely to come from the cooling of the hot corona, however it is still not clear…
High-Velocity Clouds (HVCs) are believed to be an important source of gas accretion for star formation in the Milky Way. Earlier numerical studies have found that the Galactic magnetic field and radiative cooling strongly affects accretion.…
It is argued that galaxies like ours sustain their star formation by transferring gas from an extensive corona to the star-forming disc. The transfer is effected by the galactic fountain -- cool clouds that are shot up from the plane to…
The Galactic halo contains a complex ecosystem of multiphase intermediate-velocity and high-velocity gas clouds whose origin has defied clear explanation. They are generally believed to be involved in a Galaxy-wide recycling process, either…
Galaxies must form and evolve via the acquisition of gas from the intergalactic environment, however the way this gas accretion takes place is still poorly understood. Star-forming galaxies are surrounded by multiphase halos that appear to…
We investigate the physics that drives the gas accretion rates onto galaxies at the centers of dark matter haloes using the EAGLE suite of hydrodynamical cosmological simulations. We find that at redshifts $z{\le}2$ the accretion rate onto…
We present results from high--resolution cosmological hydrodynamical simulations of a Milky--Way-sized halo, aimed at studying the effect of feedback on the nature of gas accretion. Simulations include a model of inter-stellar medium and…
We use FIRE simulations to study disk formation in z~0, Milky Way-mass galaxies, and conclude that a key ingredient for the formation of thin stellar disks is the ability for accreting gas to develop an aligned angular momentum distribution…
Whether High Velocity Clouds (HVCs) can form by condensation of the hot ($T \sim 10^6 \, {\rm K}$) Galactic corona as a consequence of thermal instabilities has been controversial. Here we re-examine this problem and we suggest that…
We use high resolution cosmological hydrodynamical simulations to demonstrate that cold flow gas accretion, particularly along filaments, modifies the standard picture of gas accretion and cooling onto galaxy disks. In the standard picture,…
Studies of the halo gas in the Milky Way and in nearby spiral galaxies show the presence of gas complexes that cannot be reconciled with an internal (galactic fountain) origin and are direct evidence of gas accretion. Estimating gas…
We use high-resolution cosmological hydrodynamical simulations of Milky Way-sized galaxies with varying supernovae feedback strengths and merger histories to investigate the formation of their gaseous halos and especially their hot…
Different from Milky-Way-like galaxies, discs of gas-rich galaxies are clumpy. It is believed that the clumps form because of gravitational instability. However, a necessary condition for gravitational instability to develop is that the…