Mapping the Distorted Dark Matter Distribution of the LMC-SMC System Prior to Milky Way Infall with Basis Function Expansions

Abstract

The SMC orbits within the LMC's dark matter (DM) halo in a $\sim$1:10 mass-ratio encounter. The LMC:Milky Way (MW) interaction is also $\sim$1:10, and is expected to perturb the MW's DM distribution. However, no framework exists to quantify the severity of these perturbations over multiple pericenters and longer periods of time, such as the LMC-SMC interaction history. We construct basis function expansions of a high-resolution \textit{N}-body simulation of the Clouds interacting in isolation and analyze their DM distributions at an epoch approximating the time of their infall to the MW. Our goal is to quantify how the Clouds distort each other's DM distributions \textit{without} the MW. The LMC halo's response to the SMC includes a $\sim 20$ kpc long dynamical friction wake and the displacement of the LMC's density center during each SMC pericenter, which produces two overdensities in the LMC halo (at $\sim$60 and $\sim$100 kpc) at MW infall. The SMC's tidal radius at infall is just $\sim 4$ kpc, at which point the SMC has lost two-thirds of its initial DM mass to the LMC. The distortions to the Clouds' halos produce a highly asymmetric acceleration field. Accurate orbit integration in the LMC-SMC system must account for the time-dependent shapes of both halos. The SMC-induced perturbations in the LMC DM halo resemble the MW-LMC system, and persist over multiple SMC pericenters. We conclude that 1:10 satellite-host encounters induce characteristic deformations in both DM halos across host-mass scales, with implications for merger rates and tests of DM models.

31 pages, 21 figures, 4 tables, 1 appendix. Updated for consistency with published version

References in corpus (55)

• Array Programming with NumPy
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Is the SMC Bound to the LMC? The HST Proper Motion of the SMC
• Small Dwarf Galaxies Within Larger Dwarfs: Why Some Are Luminous While Most Go Dark
• TiNy Titans: The Role of Dwarf-Dwarf Interactions in the Evolution of Low Mass Galaxies
• Proper Motions, Orbits, and Tidal Influences of Milky Way Dwarf Spheroidal Galaxies
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• Clouds, Streams and Bridges. Redrawing the blueprint of the Magellanic System with Gaia DR1
• The M31 Velocity Vector. III. Future Milky Way-M31-M33 Orbital Evolution, Merging, and Fate of the Sun
• Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall
• Dynamics of the Magellanic Clouds in a LCDM Universe
• Reflex motion in the Milky Way stellar halo resulting from the Large Magellanic Cloud infall
• Core-collapse, evaporation and tidal effects: the life story of a self-interacting dark matter subhalo
• Galaxy And Mass Assembly (GAMA): In Search of Milky-Way Magellanic Cloud Analogues
• The effect of the LMC on the Milky Way system
• The synchronised dance of the Magellanic Clouds' star formation history
• The effect of the deforming dark matter haloes of the Milky Way and the Large Magellanic Cloud on the Orphan-Chenab stream
• The Pisces Plume and the Magellanic Wake
• A Self-interacting Dark Matter Solution to the Extreme Diversity of Low-mass Halo Properties
• The recent LMC-SMC collision: Timing and impact parameter constraints from comparison of Gaia LMC disk kinematics and N-body simulations
• The Magellanic Corona and the formation of the Magellanic Stream
• Quantifying the Stellar Halo's Response to the LMC's Infall with Spherical Harmonics
• The LMC geometry and outer stellar populations from early DES data
• The SAGA Survey. III. A Census of 101 Satellite Systems around Milky Way-mass Galaxies
• The Magellanic System: the puzzle of the leading gas stream
• Discovery of the Magellanic Stellar Stream Out to 100 Kiloparsecs
• The impact of galactic feedback on the shapes of dark-matter haloes
• The Magellanic Edges Survey I. Description and First Results
• Mapping the anisotropic Galactic stellar halo with Blue Horizontal Branch stars
• Structure, Kinematics, and Observability of the Large Magellanic Cloud's Dynamical Friction Wake in Cold vs. Fuzzy Dark Matter
• Exploring the interaction between the MW and LMC with a large sample of blue horizontal branch stars from the DESI survey
• Effect of low-mass galaxy interactions on their star formation
• All-Sky Kinematics of the Distant Halo: The Reflex Response to the LMC
• Shape of the outer stellar warp in the Large Magellanic Cloud disk
• Vertical structure and kinematics of the LMC disc from SDSS/Gaia
• Equilibrium dynamical models in the inner region of the Large Magellanic Cloud based on Gaia DR3 kinematics
• Precise Measurements of the LMC Bar's Geometry With Gaia DR3 and a Novel Solution to Crowding Induced Incompleteness in Star Counting
• Shaping the Milky Way: The interplay of mergers and cosmic filaments
• Tidal interaction can stop galactic bars: on the LMC non-rotating bar
• ULDM self-interactions, tidal effects and tunnelling out of satellite galaxies
• A determination of the LMC dark matter subhalo mass using the MW halo stars in its gravitational wake
• Thermalization, Fragmentation and Tidal Disruption: The Complex Galactic Dynamics of Dark Matter Superfluidity
• Response of the LMC's Bar to a Recent SMC Collision and Implications for the SMC's Dark Matter Profile
• The VMC survey -- LIV. The internal kinematics of the LMC with new VISTA observations
• Following the tidal trail: a history of modeling the Magellanic Stream
• Chemo-Dynamical Tagging in the Outskirts: The Origins of Stellar Substructures in the Magellanic Clouds
• UVIT Study of the MAgellanic Clouds (U-SMAC) I. Recent star formation history and kinematics of the Shell region in the North-Eastern Small Magellanic Cloud
• UVIT view of NGC 5291: Ongoing star formation in tidal dwarf galaxies at ~ 0.35 kpc resolution
• EXP: a Python/C++ package for basis function expansion methods in galactic dynamics
• A general basis set algorithm for galactic haloes and discs
• A Simulation Based Inference Approach to the Dynamics of the MW-LMC System -- Validation
• Untangling Magellanic Streams
• A Galactic Transformation -- Understanding the SMC's Structural and Kinematic Disequilibrium
• Star formation in interacting galaxy systems: UVIT imaging of NGC 7252 and NGC 5291
• Threading the Magellanic Needle: Hypervelocity Stars Trace the Past Location of the LMC