Ghostly Stellar Halos in Dwarf Galaxies

Abstract

Our study aims at probing the typical masses of the smallest and faintest galaxies that have ever formed in the universe. We carry out numerical simulations to characterize the size, stellar mass, and stellar mass surface density of stellar halos as a function of dark matter halo mass and a parameter that dictates the amount of stellar mass. We expect that for galaxies smaller than a critical value, these ghostly halos will not exist because the smaller galactic subunits that build it up, do not form any stars. Our results indicate the introduced parameter dominates the behaviors of stellar halos over dark matter mass. This indicates finding the appropriate parameter value is crucial to characterize these halos. We also find redshift contributes to the behavior of stellar mass but has no significant impact on the size of stellar halos.