Chasing Tidal Tails Around the Milky Way

Thursday, 12 May 2016 2 p.m. — 3 p.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
ANA BONACA (Yale University and NOAO South Visiting Astronomer)

Stars in the halo of the Milky Way have long dynamical times and thus retain a record of their past accretion into the gravitational potential of the Milky Way. To date, remnants of over 25 Milky Way satellites have been identified in the Galactic halo. These stellar streams are powerful constraints of the gravitational potential, but because the true potential form is unknown, individual streams can produce very biased results. Most potential recovery methods rely on full, observationally expensive, 6D information for the stream member stars. Consequently, current constraints of the Milky Way potential are based on individual streams, with some tension between different streams. These discrepancies can be resolved by simultaneously modeling multiple stellar streams that have been discovered in the Galactic halo. We use two most prominent cold streams in the Milky Way, tidal tails of the Palomar 5 globular cluster and GD-1 stream, to measure the global properties of our dark matter halo. Based on the analysis of synthetic streams on similar orbits, we discuss which new data would most improve our understanding of the Galactic gravitational potential.