Numerical Simulations of Bubble-Induced Star Formation in Dwarf Irregular Galaxies with a Novel Stellar Feedback Scheme

TL;DR

This study uses advanced simulations to explore how bubble collisions from stellar feedback can trigger widespread star formation in dwarf irregular galaxies, revealing unique mechanisms distinct from larger galaxies.

Contribution

Introduces a novel stellar feedback scheme in simulations that demonstrates bubble collisions induce star formation and influence metallicity and stellar dynamics in dwarf irregular galaxies.

Findings

Bubble collisions trigger widespread star formation.

Metallicity in star-forming regions remains low.

Bubble-induced star formation leads to counter-rotating stars.

Abstract

To study the star formation and feedback mechanism, we simulate the evolution of an isolated dwarf irregular galaxy (dIrr) in a fixed dark matter halo, similar in size to WLM, using a new stellar feedback scheme. We use the new version of our original N-body/smoothed particle chemodynamics code, GCD+, which adopts improved hydrodynamics, metal diffusion between the gas particles and new modelling of star formation and stellar wind and supernovae (SNe) feedback. Comparing the simulations with and without stellar feedback effects, we demonstrate that the collisions of bubbles produced by strong feedback can induce star formation in a more widely spread area. We also demonstrate that the metallicity in star forming regions is kept low due to the mixing of the metal-rich bubbles and the metal-poor inter-stellar medium. Our simulations also suggest that the bubble-induced star formation leads to many counter-rotating stars. The bubble-induced star formation could be a dominant mechanism to maintain star formation in dIrrs, which is different from larger spiral galaxies where the non-axisymmetric structures, such as spiral arms, are a main driver of star formation.