Measuring Sizes of Ultra-Faint Dwarf Galaxies

Understand

The discovery of Ultra-Faint Dwarf (UFD) galaxies in the halo of the Milky Way extends the faint end of the galaxy luminosity function to a few hundred solar luminosities.

• This extremely low luminosity regime poses a significant challenge for the photometric characterization of these systems.
• We present a suite of simulations aimed at understanding how different observational choices related to the properties of a low luminosity system impact our ability to determine its true structural parameters such as half-light radius and central surface brightness.
• We focus on estimating half-light radii (on which mass estimates depend linearly) and find that these numbers can have up to 100% uncertainties when relatively shallow photometric surveys, such as SDSS, are used.