Chemodynamic evolution of dwarf galaxies in tidal fields

TL;DR

This study uses SPH simulations to explore how tidal interactions influence the metallicity and metallicity gradients of dwarf galaxies, revealing that tides mainly strip low-metallicity gas and can increase overall metallicity.

Contribution

It provides new insights into the role of tidal forces in shaping the metallicity evolution of dwarf galaxies through detailed hydrodynamic simulations.

Findings

Tides strip outer low-metallicity gas from dwarf galaxies.

Tidal effects can lead to higher overall metallicities.

Tides influence metallicity gradients and gas distribution.

Abstract

The mass-metallicity relation shows that the galaxies with the lowest mass have the lowest metallicities. As most dwarf galaxies are in group environments, interaction effects such as tides could contribute to this trend. We perform a series of smoothed particle hydrodynamics (SPH) simulations of dwarf galaxies in external tidal fields to examine the effects of tides on their metallicities and metallicity gradients. In our simulated galaxies, gravitational instabilities drive gas inwards and produce centralized star formation and a significant metallicity gradient. Strong tides can contribute to these instabilities, but their primary effect is to strip the outer low-metallicity gas, producing a truncated gas disk with a large metallicity. This suggests that the role of tides on the mass-metallicity relation is to move dwarf galaxies to higher metallicities.