English

Disentangling Drivers of Disk Warps in Tilted and Tumbling TNG50 Halos

Astrophysics of Galaxies 2026-02-03 v2

Abstract

Dark matter (DM) halos in Λ\Lambda Cold DM cosmological simulations are triaxial. Most exhibit figure rotation. We study 40 isolated halos with stellar disks from the TNG50 simulation suite across 4\sim 4~Gyr to understand whether and how a triaxial halo's tumbling and orientation relative to the disk can drive warps. We measure a warp angle ψ\psi and find even our isolated disks are all at least slightly warped, with each galaxy's maximum ψ>1.8\psi > 1.8^{\circ}. We perform a modified cross-correlation analysis between ψ\psi and the figure rotation pattern speed, as well as the misalignment between the disk spin axis and (a) the figure rotation axis, (b) the halo minor axis, and (c) the gas angular momentum axis. We use snapshots spanning a lookback time tlb 4t_{lb} ~4 Gyr with 25 linearly-spaced lags from 02.33 0 - 2.33 Gyr. We do not find evidence for a consistent lag between the onset of a warp and any of the aforementioned factors on the population level. However, we find significant correlations between individual time-series at various lags. These maximum correlation coefficients were significantly offset from random chance at the population level, suggesting that several of these factors do correlate with disk warping in specific situations. By examining four case studies whose maximum correlation coefficients were significantly higher than random chance, we establish clear qualitative relationships between these factors and warps. While a non-warped galaxy typically shows minimal halo tilt and figure rotation, warped galaxies can have strong/weak tilts and/or strong/weak figure rotation. Keywords: Disk galaxies(391), Galaxy dynamics(591), Hydrodynamical simulations(767), Galaxy DM halos(1880)

Keywords

Cite

@article{arxiv.2601.17599,
  title  = {Disentangling Drivers of Disk Warps in Tilted and Tumbling TNG50 Halos},
  author = {Saarthak Johri and Neil Ash and Monica Valluri},
  journal= {arXiv preprint arXiv:2601.17599},
  year   = {2026}
}

Comments

15 pages, 11 figures, to be submitted to Open Journal of Astrophysics