Galactic studies have been enhanced by precise astrometric and spectroscopic data from surveys like Gaia and APOGEE, enabling chemodynamical analyses of disk stellar populations and constraints on the Galactic mass distribution and accretion history. In this talk, I will discuss my application of Orbital Torus Imaging (OTI), a dynamical inference method for determining the Galactic gravitational potential, to the Feedback in Realistic Environments (FIRE-2) cosmological hydrodynamic simulation, m12i. OTI leverages stellar astrophysical quantities, like element abundances, as a function of dynamical quantities, like orbital actions, to infer potential parameters, assuming axisymmetry and steady-state. In m12i, OTI recovers the vertical acceleration profiles within 3σ/1σ errors for 94%/75% of the volumes considered. I will discuss its sensitivity to the local, instantaneous disk structure, including decreased accuracy in volumes with large (>1.5 kpc) scale heights and low total density at z=1.1 kpc. Moreover, I will discuss the chemodynamical signatures of accreted moving groups in FIRE-2 galaxy m12f, originating from the merger between a Milky Way-mass host with a Sagittarius dwarf spheroidal-mass satellite. Despite the dynamically active, gas-rich disk, these groups travel together for ≳1 Gyr following the merger. Ex situ groups form clumps on the periphery of the Lz − vR plane and show strong correlations between stellar formation radius and [Fe/H], total energy, and radial actions, while age, [Mg/Fe], and vertical actions are less correlated. These results motivate searches for accreted debris in the disk to reconstruct the Milky Way’s assembly history.
Using Stellar Chemistry and Phase-Space Distribution to Constrain Galactic Potential Parameters & Accretion History
Jeudi 22 octobre 2026
de
11:00 à
12:00
Conference room, building 17
