Disentangling Streams in the Halo using RR Lyrae Stars

Monday, 13 May 2013 2 p.m. — 3 p.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
ANNA KATHERINA VIVAS (Centro de Investigaciones de Astronomia (CIDA), Venezuela and Candidate to CTIO Scientific Staff)

The halo of the Milky Way is expected to be filled with stellar streams from disrupted dwarf galaxies. The study of those streams is important to understand the role of mergers in the formation of galaxies like the Milky Way. RR Lyrae stars play an important role in the discovery and characterization of streams in the halo because they are both old stars and standard candles. Furthermore, if kinematics is available, streams can be recognized in phase space. This has proven to be specially useful in the Virgo region where a large overdensity of stars at a distance of ~20 kpc is known to exist. Initially interpreted as a single accretion event, today we believe, based on the results from RR Lyrae stars, that several different stellar streams lie along the same line of sight.