How the first stars shaped the faintest gas-dominated dwarf galaxies

TL;DR

This paper uses new simulations to show how the ultraviolet radiation from the first stars influences the formation and observable properties of the faintest gas-rich dwarf galaxies, aligning models with real observations.

Contribution

It introduces a simulation approach that incorporates the effects of early star radiation, resolving previous conflicts in understanding faint dwarf galaxy properties within standard cosmology.

Findings

Simulations reproduce observed properties of faint dwarf galaxies.

Galaxies follow the baryonic Tully-Fisher relation.

The model aligns with chemical, kinematical, and structural data.

Abstract

Low-mass dwarf galaxies are very sensitive test-beds for theories of cosmic structure formation since their weak gravitational fields allow the effects of the relevant physical processes to clearly stand out. Up to now, no unified account exists of the sometimes seemingly conflicting properties of the faintest isolated dwarfs in and around the Local Group, such as Leo T and the recently discovered Leo P and Pisces A systems. Using new numerical simulations, we show that this serious challenge to our understanding of galaxy formation can be effectively resolved by taking into account the regulating influence of the ultraviolet radiation of the first population of stars on a dwarf's star formation rate while otherwise staying within the standard cosmological paradigm for structure formation. These simulations produce faint, gas-dominated, star-forming dwarf galaxies that lie on the baryonic Tully-Fisher relation and that successfully reproduce a broad range of chemical, kinematical, and structural observables of real late-type dwarf galaxies. Furthermore, we stress the importance of obtaining properties of simulated galaxies in a manner as close as possible to the typically employed observational techniques.