Feedback and the Formation of Dwarf Galaxy Stellar Halos

TL;DR

This study uses SPH simulations to show that early star formation and supernova feedback can create extended stellar halos in dwarf galaxies, without requiring accretion of smaller systems.

Contribution

It demonstrates that internal feedback processes alone can produce stellar halos in dwarf galaxies, challenging the idea that halos form mainly through accretion.

Findings

Simulations reproduce extended stellar halos in dwarf galaxies.

Early star formation and supernova feedback are key to halo formation.

Halo-like structures form without subhalo accretion.

Abstract

Stellar population studies show that low mass galaxies in all environments exhibit stellar halos that are older and more spherically distributed than the main body of the galaxy. In some cases, there is a significant intermediate age component that extends beyond the young disk. We examine a suite of Smoothed Particle Hydrodynamic (SPH) simulations and find that elevated early star formation activity combined with supernova feedback can produce an extended stellar distribution that resembles these halos for model galaxies ranging from $v_{200}$ = 15 km s$^{-1}$ to 35 km s$^{-1}$, without the need for accretion of subhalos.