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Studying the Milky Way Evolution with SPH + N-body Models

Title: Studying the Milky Way Evolution with SPH + N-body Models

Speaker: Dr. Joao Antonio Amarante (SDSS-V collaboration)

Time: 10:00am, July 17, 2023

Location: 5-516, PMO Xianlin Campus

Abstract: The Milky Way experienced several merger events which left their imprints on the stellar halo. In particular, it is known that a major merger happened during the Galaxy’s first Gyrs and, likely, perturbed its disc-shape structure. In order to fully understand the effects of such an event, we need to know the chemical and dynamical characteristics of the young Milky Way, i.e., before the major merger event, and the accreted satellite. For this purpose, SPH + N-body models guide us to explore formation scenarios of Milky Way-like galaxies that went through similar merger events. Such idealized models enable us to control the initial conditions of the merger and which physical processes are included, therefore understanding them better. This talk is divided into three parts. First, I explore the evolution of isolated simulation galaxies with different star formation prescriptions and find evidence which supports a clumpy phase of star formation in the young Galaxy. For instance, the kinematic and chemical properties of stars near the Sun, commonly associated with the effects of a merger, can be explained by a clumpy formation scenario. This scenario is supported by observations of high redshift (z>1) galaxies with highly dense clumpy regions. Secondly, I introduce the Gaia-EncelAdus-Sausage Timing, chemistRy and Orbit (GASTRO) library: a suite of simulations exploring the parameter space for GSE-like accretion events and its impact on the formation history of the MW. Finally, I use a subset of the GASTRO library and explore the chemodynamical properties of the accreted stars and the implications to the known substructures in the stellar halo of our Galaxy.