Fantastic Clumps and Where to Find Them: A Study of the Assembly History of the Milky Way

Harshil Kamdar, Harvard University

Photo of Harshil Kamdar

The Gaia space mission has provided us with the positions and velocities of more than a billion stars in the Milky Way. This unprecedented data set opens up a lot of avenues to study how our galaxy was born and how it evolved over cosmic time and will help us with more general questions about the life cycle of galaxies in a cosmological context. Combined with ground-based astronomical surveys that can measure the chemical makeup of individual stars, Gaia can answer questions about how our galaxy was born and assembled. We present a set of solar-mass resolution simulations of a Milky Way-like galaxy to study the dynamical and chemical evolution of our galaxy. In particular, I will focus on the algorithms we have developed and used to find coherent clumps in the chemical space spanned by millions of stars in our simulations in hopes of finding families of stars born together and perhaps the sun's siblings in Gaia. Moreover, I will also discuss what the position and velocity space structure of our immediate solar neighborhood looks like and the impact of the galaxy's bar and spiral arms on this structure. Comparing to our simulations, we find that stars clustered in Gaia may not necessarily be co-natal. However, Gaia, combined with other ground-based spectroscopic surveys, has the potential to let us probabilistically model the combined chemodynamical space spanned by the stars in our galaxy.

Abstract Author(s): Harshil Kamdar