Colloquium: How diverse are the faintest dwarf galaxies

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Recent advances in imaging capabilities have transformed our understanding of galaxies at the low surface brightnesses frontier, unveiling a new population of ever smaller "ultra-faint" dwarf galaxies. Such low-mass, feeble objects are highly sensitive to the physical processes that shape galaxies in our Universe, providing an ideal laboratory for testing galaxy formation models. This same sensitivity, however, also generates extended scatter in their properties, which is essential to quantify to interpret findings in the next generation of deep, wide sky, surveys.

To begin this quantification, I present results from "genetically modified" cosmological simulations of galaxies, allowing us to uniquely separate the role of cosmological assemblies and physical models in a given galaxy's final observables. I will show how this combination of abilities enables us to extract the expected diversity in the stellar and gaseous properties of the faintest galaxies in our Universe, making testable predictions that can be harnessed to constrain interstellar medium models with near-future photometric and radio surveys.