CCA Seminar (Elena D’Onghia Talk)

Date & Time

“Next Frontiers in the Stellar Dynamics of the Milky Way”

Can we understand the origin of the stars in the Galactic halo? Ongoing surveys promise to revolutionize our understanding of the Milky Way dynamics, in particular of the stellar halo and disk. The Galactic halo is expected to be populated by several stellar streams stripped from dwarf galaxies and globular clusters orbiting around the Milky Way. Can we discover new streams with ongoing missions like Gaia-ESO and APOGEE data?

My work serves the mission of CCA by providing a novel technique based on a new statistical method that searches for kinematically– and chemically–clustered stars in the APOGEE-2 data. The new statistical algorithm applied to the current data identifies globular clusters without knowing a priori where they are located on the sky and identifies the stars that are members of the known globular clusters (within a 95% confidence level). Thus, not only does this technique promise to discover new globular clusters, but it also allows us to search for unusual stars in the halo to identify new streams of kinematically– and chemically–clustered stars.

In the disk the associations of stars with coherent velocities are among the most intriguing systems that we can study in greater detail. Their existence in the solar neighborhood shows that the Galactic stellar disk is far from being uniform in its velocity distribution. By performing high-resolution N-body experiments I address the role of spiral arms in the evolution of such associations of stars and their nature. These new studies combined with observational facilities allow us to discover additional associations of stars outside the solar neighborhood, opening up the next frontier in the study of stellar dynamics.

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