Gas Content of Interacting Pairs of Dwarf Galaxies

Pearson et al. (2016) present a study of 10 interacting pairs of dwarf galaxies in the Local Universe. The gas content of these galaxies appears more extended compared to isolated dwarf galaxies. For interacting pairs of dwarf galaxies that evolve in isolation, the gas content is bound and not lost to the surroundings. However, this is not the case for interacting pairs of dwarf galaxies located near massive host galaxies as their gas content can become lost to the surroundings.

Interacting pairs of dwarf galaxies can have a large amount of their gas content moved to the outskirts. Over ~50 percent of their gas content can be moved to the outskirts. For interacting pairs of dwarf galaxies that are evolving in isolation, the gas content "parked" in the outskirts can be re-accreted to drive future star formation. As for interacting pairs of dwarf galaxies that evolve in the vicinity of massive host galaxies, not only can they lose their gas content, they are also morphologically shaped by their environment and they can take on asymmetric profiles.

Of the 10 interacting pairs of dwarf galaxies in this study, 7 appear to have dense bridges of gas connecting them. The density of the gas content in these bridges is higher than the gas content in the surrounding regions. This explains why star formation can occur in these regions but not elsewhere. Ultimately, it is the proximity with massive host galaxies that drives the lost of gas content from interacting pairs of dwarf galaxies, and not due to mutual interactions between the dwarf galaxies themselves.

Reference:
"Local Volume TiNy Titans: Gaseous Dwarf-Dwarf Interactions in the Local Universe", arXiv:1603.09342 [astro-ph.GA]