Azimuthal Misalignments in Stellar Warp Structure as Dynamical Tracers of Mergers in Milky Way-like Galaxies
arXiv:2510.04194 · doi:10.3847/2041-8213/ae11b4
Abstract
We investigate the origin of warps in stellar disks using high-resolution Milky Way analogs from the IllustrisTNG50 simulation. Focusing on galaxies that experienced a major merger, we identify a characteristic azimuthal misalignment between the warp structures of stellar populations formed before and after the merger. This misalignment persists even after correcting for differential rotation, suggesting it is a dynamical imprint of the merger rather than a consequence of internal kinematics. In contrast, galaxies without significant merger events show no such offset between stellar populations of different ages. These findings support the scenario in which mergers can induce long-lived warps and leave detectable structural signatures in stellar disks. Applied to the Milky Way, this approach offers a potential way to test whether the Gaia-Sausage-Enceladus merger contributed to the formation of the Galactic warp. It may also provide an independent means to constrain the timing of such merger events by examining the phase offsets in the stellar warp as a function of stellar age.
References in corpus (53)
- Gaia Data Release 2. Summary of the contents and survey properties
- 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
- First Results from the TNG50 Simulation: Galactic outflows driven by supernovae and black hole feedback
- First Results from the TNG50 Simulation: The evolution of stellar and gaseous disks across cosmic time
- Three Dimensional Structure of the Milky Way Disk
- Old stellar Galactic disc in near-plane regions according to 2MASS: scales, cut-off, flare and warp
- The Influence of Sagittarius and the Large Magellanic Cloud on the Milky Way Galaxy
- The Vertical Structure of the Outer Milky Way HI Disk
- 4MOST - 4-metre Multi-Object Spectroscopic Telescope
- Deciphering The Last Major Invasion of the Milky Way Galaxy
- Neutral Hydrogen and Optical Observations of Edge-on Galaxies: Hunting for Warps
- The Milky Way's external disc constrained by 2MASS star counts
- An intuitive 3D map of the Galactic warp's precession traced by classical Cepheids
- Warp, Waves, and Wrinkles in the Milky Way
- A Magellanic Origin for the Warp of the Galaxy
- Galactic Warps Induced By Cosmic Infall
- The Galactic warp revealed by Gaia DR2 kinematics
- Warps and waves in the stellar discs of the Auriga cosmological simulations
- A fully cosmological model of a Monoceros-like ring
- Evidence of a dynamically evolving Galactic warp
- Excitation of coupled stellar motions in the Galactic Disk by orbiting satellites
- Evolution over time of the Milky Way's disc shape
- Generation of galactic disc warps due to intergalactic accretion flows onto the disc
- Mapping the Milky Way with LAMOST III: Complicated spatial structure in the outer disc
- Bending Waves in the Milky Way's disc from halo substructure
- Merger-induced galaxy transformations in the ARTEMIS simulations
- Gaia kinematics reveal a complex lopsided and twisted Galactic disc warp
- Formation of Warped Disks by Galactic Fly-by Encounters. I. Stellar Disks
- Exploring the Galactic Warp Through Asymmetries in the Kinematics of the Galactic Disk
- Evidence for coupling between the Sagittarius dwarf galaxy and the Milky Way warp
- Mapping the Galactic disk with the LAMOST and Gaia Red clump sample. VI: An evidence for the long lived non-steady warp of non-gravitational scenarios
- A Tilted Dark Halo Origin of the Galactic Disk Warp and Flare
- Phase Wrapping of Epicyclic Perturbations in the Wobbly Galaxy
- Tracing the Milky Way warp and spiral arms with classical Cepheids
- Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample VII: the Stellar Disk Structure Revealed by the Mono-abundance Populations
- Vertical velocities from proper motions of red clump giants
- Tidally induced warps of spiral galaxies in IllustrisTNG
- Galaxies with conspicuous optical warps
- On the kinematic signature of the Galactic warp as revealed by the LAMOST-TGAS data
- Structure of the outer Galactic disc with Gaia-DR2
- Warp and flare of the Galactic disc revealed with supergiants by Gaia EDR3
- A twisted and precessing Cepheid warp in the outer Milky Way disc
- Warp and flare of the old Galactic disc as traced by the red clump stars
- Mapping the Galactic disk with the LAMOST and Gaia red clump sample: IV: the kinematic signature of the Galactic warp
- The tangled warp of the Milky Way
- The line-of-sight warp of the spiral galaxy ESO 123-G23
- Evidence for Populations-dependent vertical motions and the Long-lived Non-Steady Lopsided Milky Way Warp
- Tidal Torques and Galactic Warps
- Exploring the structure and kinematics of the Milky Way through A stars
- Galactic warps: from cosmic noon to the current epoch