[IPARCOS astro-seminar] 11/10/24

Jonah Gannon (Swinburne University of Technology, Australia)

Title: The Building Evidence that Some Ultra-Diffuse Galaxies are 'Failed Galaxies'

Abstract: In this talk, I present an overview of the current formation constraints on ultra-diffuse galaxies based on optical spectroscopy measurements. In particular, I will focus on their mass measurements with current evidence suggesting that there is a diverse range of halo masses and halo profiles in the ultra-diffuse galaxy regime. I will show that many mass measurements suggest some ultra-diffuse galaxies do not reside in dwarf-like dark matter halos, but are more massive indicative of a dark matter halo that has failed to form the stellar mass that is usually expected. I will also present work from our group that these "failed galaxies" are distinct from the remaining population and may be relics of z~2 galaxy formation. These "failed galaxy" ultra-diffuse galaxies are currently unsimulated and need to be reconciled with our understanding dwarf galaxy formation. The talk is enabled by a publicly available catalogue of ultra-diffuse galaxy spectroscopic properties with details provided for its access and use in the talk.