The Role of Dark Matter in Driving Disk Perturbations: Application to LMC–SMC-like Galaxy Interactions

@article{rathore2026role,
  title = {{The Role of Dark Matter in Driving Disk Perturbations: Application to LMC–SMC-like Galaxy Interactions}},
  author = {Himansh Rathore and Hayden R. Foote and Gurtina Besla and Silvio Varela-Lavin and Nicolás Garavito-Camargo and Martin D. Weinberg and Facundo A. Gómez and Kathryne J. Daniel and Chervin F. P. Laporte and The EXP Collaboration},
  journal = {The Astrophysical Journal},
  year = {2026},
  month = nov,
  doi = {10.3847/1538-4357/aeaf50},
  url = {https://iopscience.iop.org/article/10.3847/1538-4357/aeaf50},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - The Role of Dark Matter in Driving Disk Perturbations: Application to LMC–SMC-like Galaxy Interactions
AU  - Himansh Rathore
AU  - Hayden R. Foote
AU  - Gurtina Besla
AU  - Silvio Varela-Lavin
AU  - Nicolás Garavito-Camargo
AU  - Martin D. Weinberg
AU  - Facundo A. Gómez
AU  - Kathryne J. Daniel
AU  - Chervin F. P. Laporte
AU  - The EXP Collaboration
PY  - 2026
DA  - 2026/11/02
JO  - The Astrophysical Journal
DO  - 10.3847/1538-4357/aeaf50
UR  - https://iopscience.iop.org/article/10.3847/1538-4357/aeaf50
AB  - Dark matter (DM) models predict that satellite galaxies distort their host’s DM halo. As such, both the satellite and the distorted halo can perturb the host’s stellar disk. The LMC–SMC system is a nearby ∼1:10 mass ratio binary with a well-constrained orbit and well-characterized LMC disk perturbations. Hence, the system offers unique opportunities to test DM theory, provided the impact of halo torques on the LMC’s disk can be characterized along with the SMC’s torques. We use halo Basis Function Expansions (BFEs) of an N -body simulation of an isolated LMC–SMC-like interaction to quantify the time-dependent torques exerted on the LMC’s disk by the SMC and the LMC’s DM halo. We find that the halo torques arise from the quadrupole halo distortion, and the inner ( R < 6 kpc) LMC disk warps are the most promising probe of this quadrupole. For the first time, we construct a BFE to quantify the LMC’s disk perturbations resulting from the SMC and halo torques. We find that the LMC’s disk is significantly perturbed prior to the Clouds’ Milky Way infall, possessing warps with a mean vertical extent of ∼1 kpc. Finally, we apply multichannel singular spectral analysis (mSSA) to the time series of the disk BFE coefficients, halo quadrupole, and the LMC-SMC orbit. mSSA successfully separates the temporal evolution of the LMC warps into components correlated with the halo versus the SMC. Our framework identifies correlated evolution between the LMC’s halo distortions and the LMC’s disk perturbations, enabling the Clouds to be a precision laboratory for DM physics.
SN  - 1538-4357
SN  - 0004-637X
ER  -