Stellar Metallicities from DECam $u$-band Photometry: A Study of Milky Way Ultra-Faint Dwarf Galaxies

Understand

We conducted an in-depth analysis of candidate member stars located in the peripheries of three ultra-faint dwarf (UFD) galaxy satellites of the Milky Way: Bo\"otes I (Boo1), Bo\"otes II (Boo2), and Segue I (Seg1).

• Studying these peripheral stars has previously been difficult due to contamination from the Milky Way foreground.
• We used $u$-band photometry from the Dark Energy Camera (DECam) to derive metallicities to efficiently select UFD candidate member stars.
• This approach was validated on Boo1, where we identified both previously known and new candidate member stars beyond five half-light radii.