Accelerated phase-mixing in the stellar halo due to a rotating bar
arXiv:2301.04154 · doi:10.1093/mnrasl/slad017
Abstract
In a galaxy merger, the stars tidally stripped from the satellite and accreted onto the host galaxy undergo phase mixing and form finely-grained structures in the phase space. However, these fragile structures may be destroyed in the subsequent galaxy evolution, in particular, by a rotating bar that appears well after the merger is completed. In this work, we investigate the survivability of phase-space structures in the presence of a bar. We find that a bar with amplitude and pattern speed similar to those of the Milky Way would blur and destroy a substantial amount of the substructure that consists of particles with pericentre radii comparable to the bar length. While this appears to be in tension with the recent discovery of phase-space chevrons in \textit{Gaia} DR3 data, the most prominent chevrons in our simulations can still be recovered when applying the same analysis procedure as in observations. Moreover, the smoothing effect is less pronounced in the population of stars whose angular momenta have the opposite sign to the bar pattern speed.
arXiv comment5 pages, 7 figures, accepted by MNRAS
References in corpus (26)
- The Gaia mission
- Gaia Data Release 3: Summary of the content and survey properties
- The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
- Co-formation of the Galactic disc and the stellar halo
- AGAMA: Action-based galaxy modelling architecture
- The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
- The Structure of the Milky Way's Bar Outside the Bulge
- Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
- The population of barred galaxies in the local universe I. Detection and characterisation of bars
- A Hierarchical O(N) Force Calculation Algorithm
- Broken and unbroken: the Milky Way and M31 stellar haloes
- Separation of Stellar Populations by an Evolving Bar: Implications for the Bulge of the Milky Way
- Reconstructing the Last Major Merger of the Milky Way with the H3 Survey
- The pattern speed of the Milky Way bar from transverse velocities
- The shape of the Galactic halo with DR2 RR Lyrae. Anatomy of an ancient major merger
- The origin of galactic metal-rich stellar halo components with highly eccentric orbits
- Kinematics at the Edge of the Galactic Bulge: Evidence for Cylindrical Rotation
- The effects of bar-spiral coupling on stellar kinematics in the Galaxy
- The Halo's Ancient Metal-Rich Progenitor Revealed with BHB Stars
- A direct measurement of the distance to the Galactic center using the kinematics of bar stars
- Gas Dynamics in the Galaxy: Total Mass Distribution and the Bar Pattern Speed
- Merger-induced galaxy transformations in the ARTEMIS simulations
- An analytical phase-space model for tidal caustics
- Dynamically constraining the length of the Milky Way bar
- How Unusual is the Milky Way's Assembly History?
- A 6-d View of Stellar Shells