Uncovering Multiple Populations in NGC 7099 (M 30) using Washington
  Photometry
  Over the last decade, the classical definition of Globular Clusters (GCs) as
simple stellar populations was revolutionized due to the discovery of "Multiple
Populations" (MPs). However, our knowledge of this phenomenon and its
characteristics is still lacking greatly observationally, and there is
currently no scenario that adequately explains its origin. It is therefore
important to study as many GCs as possible to characterize whether or not they
have MPs, and determine their detailed behavior to enlighten formation
scenarios, using a wide range of techniques. The Washington photometric system
has proved to be useful to find MPs thanks mainly to the UV-sensitivity and
high efficiency of the C filter. We search for MPs in the Galactic GC NGC 7099
(M30), the second GC being searched for MPs using this system. We obtained
photometric data using the Swope 1m telescope at Las Campanas Observatory, as
well as the 4m SOAR facility. Our reduction procedure included addstar
experiments to properly assess photometric errors. We find a clear signal of
MPs based on an intrinsically wide color spread on the RGB, in particular due
to a relatively small fraction of stars significantly bluer than the main RGB
locus. These stars should correspond to so-called first generation stars, which
we estimate to be roughly 15\% of the total. However, we find these
first-generation stars to be more spatially concentrated than their second
generation counterparts, which is the opposite to the general trend found in
other clusters. We briefly discuss possible explanations for this phenomenon.
