Hot-mode versus cold-mode circumgalactic accretion

Determine whether hot-mode or cold-mode accretion is the dominant mechanism supplying circumgalactic gas to spiral galaxies, and establish how the competing mechanisms affect host-galaxy evolution and properties.

Background

The paper identifies two principal mechanisms for circumgalactic gas accretion: hot-mode accretion, in which gas is shock-heated to the virial temperature before cooling and falling toward the disk, and cold-mode accretion, in which gas arrives through filamentary or sheetlike structures without substantial shock heating. The relative importance of these mechanisms remains unresolved because the characteristic scale of cold gas is difficult to observe and simulate, and because their consequences for galaxy evolution are not fully understood.