Wednesday

As the smallest and least luminous galaxies in the Universe, Ultra-Faint Dwarf Galaxies (UFDGs) carry key evidence that can shed light on fundamental galactic processes. Within this context, the ‘Engineering Dwarfs at Galaxy Formation’s Edge’ (EDGE) project is designed to study these hidden galaxies in a cosmological dark matter simulation of a 50 Mpc void region. Multiple UFDGs, presenting elongated regions of stellar detritus and clear metallicity gradients, have already been discovered in isolated regions of the simulation. These distinguishable features, with extremely metal-poor stars situated in the outer regions, are also seen in observed UFDGs, such as in the case of the ultra-faint Tucana II.

I present here, an investigation of the internal stellar structure of the EDGE UFDGs, in order to gain insight into why the above shapes and metallicity gradients are prevalent in these dark matter-dominated systems. I compare the derived structural parameters for the EDGE UFDGs to those of the observed UFDGs. The EDGE parameters are obtained using the same Maximum Likelihood method used by observational astronomers to uncover the structural parameters of dwarf galaxies. I discuss the origins ofthe isolated stars in the EDGE galaxies as clues to understand their morphological histories. I argue here whether these stars in the outskirts are possibly owing to an early galactic merger or some other event that could warrant the steep metallicity gradients.