Digging deeper into the Southern skies: a compact Milky-Way companion
  discovered in first-year Dark Energy Survey data
  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. The most conspicuous density peaks in these maps have
been identified automatically and ranked according to their significance and
recurrence for different input models. We report the discovery of one
additional stellar system besides those previously found by several authors
using the same first-year DES data. The object is compact, and consistent with
being dominated by an old and metal-poor population. DES J0034-4902 is found at
high significance and appears in the DES images as a compact concentration of
faint blue point sources at ~ 87 {kpc}. Its half-light radius of r_h = 9.88 +/-
4.31 {pc} and total luminosity of M_V ~ -3.05_{-0.42}^{+0.69} are consistent
with it being a low mass halo cluster. It is also found to have a very
elongated shape. In addition, our deeper probe of DES 1st year data confirms
the recently reported satellite galaxy candidate Horologium II as a significant
stellar overdensity. We also infer its structural properties and compare them
to those reported in the literature.
