Efficiency of gas cooling and accretion at the disc-corona interface

TL;DR

This study uses hydrodynamical simulations to investigate how gas cooling and accretion at the disc-corona interface vary across different galactic environments, highlighting the impact of virial mass and galaxy type on gas condensation.

Contribution

It provides new insights into the role of thermal conduction and galactic environment in gas condensation processes at the disc-corona interface through detailed simulations.

Findings

Gas condensation efficiency decreases with increasing halo virial temperature.

Condensation is ineffective in halos larger than 10^13 solar masses.

Cooling and accretion are more efficient in low to intermediate mass halos.

Abstract

In star-forming galaxies, stellar feedback can have a dual effect on the circumgalactic medium both suppressing and stimulating gas accretion. The trigger of gas accretion can be caused by disc material ejected into the halo in the form of fountain clouds and by its interaction with the surrounding hot corona. Indeed, at the disc-corona interface, the mixing between the cold/metal-rich disc gas (T <~ 10^4 K) and the hot coronal gas (T >~ 10^6 K) can dramatically reduce the cooling time of a portion of the corona and produce its condensation and accretion. We studied the interaction between fountain clouds and corona in different galactic environments through parsec-scale hydrodynamical simulations, including the presence of thermal conduction, a key mechanism that influences gas condensation. Our simulations showed that the coronal gas condensation strongly depends on the galactic environment, in particular it is less efficient for increasing virial temperature/mass of the haloes where galaxies reside and it is fully ineffective for objects with virial masses larger than 10^13 Msun. This result implies that the coronal gas cools down quickly in haloes with low-intermediate virial mass (Mvir <~ 3 x 10^12 Msun) but the ability to cool the corona decreases going from late-type to early-type disc galaxies, potentially leading to the switching off of accretion and the quenching of star formation in massive systems.