A Deeper Look at Leo IV: Star Formation History and Extended Structure

Understand

We present MMT/Megacam imaging of the Leo~IV dwarf galaxy in order to investigate its structure and star formation history, and to search for signs of association with the recently discovered Leo~V satellite.

• Based on parameterized fits, we find that Leo~IV is round, with $\epsilon < 0.23$ (at the 68\% confidence limit) and a half-light radius of $r_{h} \simeq 130$ pc.
• Additionally, we perform a thorough search for extended structures in the plane of the sky and along the line of sight.
• We derive our surface brightness detection limit by implanting fake structures into our catalog with stellar populations identical to that of Leo~IV.