Digging deeper into the Southern skies: a compact Milky-Way companion discovered in first-year Dark Energy Survey data

Understand

The Dark Energy Survey (DES) is a 5000 sq.

• degree survey in the southern hemisphere, which is rapidly reducing the existing north-south asymmetry in the census of MW satellites and other stellar substructure.
• We use the first-year DES data down to previously unprobed photometric depths to search for stellar systems in the Galactic halo, therefore complementing the previous analysis of the same data carried out by our group earlier this year.
• Our search is based on a matched filter algorithm that produces stellar density maps consistent with stellar population models of various ages, metallicities, and distances over the survey area.