Multiscale Rotational–Compressive Organization in Cosmological Baryonic Flows
Abstract
Recent cosmological simulations show that baryonic matter in the cosmic web develops shocks, filamentary accretion flows, shear layers, and rotational structures. Although large-scale structure is driven by gravitational instability, the role of rotational motions in organizing baryonic flows across scales remains incompletely understood. We investigate rotational-compressive dynamics in cosmological baryonic flows using public CAMELS hydrodynamic grids from the IllustrisTNG and SIMBA suites over several epochs. From the baryonic velocity field, we derive the vorticity and define the nonlinear diagnostic S ω = ∇ • (u × ω), the divergence of the Lamb vector. Vortical structures are preferentially associated with filaments, accretion interfaces, and overdense regions. For the SIMBA realization at z = 0, Helmholtz decomposition shows that approximately 64% of the resolved velocity power is solenoidal and 36% compressive, giving an integrated ratio of about 1.8. The vorticity and nonlinear-source spectra strengthen toward low redshift, and exhibit organized multiscale behavior in both suites. The statistics further show intermittent vorticity, strong enstrophy growth, and scale-dependent correlations between the nonlinear rotational-compressive source and baryonic density fluctuations. Similar signatures in IllustrisTNG and SIMBA, despite different feedback prescriptions, indicate that these trends are robust features of nonlinear baryonic evolution. Although the available resolution does not establish fully developed turbulence, the results provide quantitative evidence that rotational motions are an important emergent component of cosmic-web dynamics and contribute to the multiscale organization of baryonic matter.
Related
- The VariableTNG project: Mass-dependent regulation of galaxy morphology by baryonic feedback
- Seeding baryonic dark matter
- WaveDM.jl: An Adaptable Simulation Framework for Dynamics of Baryonic and Wave Dark Matter on Galaxy Scales
- A two-component profile of baryonic feedback: hydrostatic and diffuse gas
- Baryonic Imprints on DM Halos: the concentration-mass relation and its dependence on 28 model parameters in the CAMELS suite
BibTeX
@article{mouhali2026multiscale,
title = {{Multiscale Rotational–Compressive Organization in Cosmological Baryonic Flows}},
author = {Waleed Mouhali},
journal = {The Astrophysical Journal},
year = {2026},
month = sep,
doi = {10.3847/1538-4357/ae9bba},
url = {https://hal.science/hal-05748758v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Multiscale Rotational–Compressive Organization in Cosmological Baryonic Flows
AU - Waleed Mouhali
PY - 2026
DA - 2026/09/08
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae9bba
UR - https://hal.science/hal-05748758v1
AB - Recent cosmological simulations show that baryonic matter in the cosmic web develops shocks, filamentary accretion flows, shear layers, and rotational structures. Although large-scale structure is driven by gravitational instability, the role of rotational motions in organizing baryonic flows across scales remains incompletely understood. We investigate rotational-compressive dynamics in cosmological baryonic flows using public CAMELS hydrodynamic grids from the IllustrisTNG and SIMBA suites over several epochs. From the baryonic velocity field, we derive the vorticity and define the nonlinear diagnostic S ω = ∇ • (u × ω), the divergence of the Lamb vector. Vortical structures are preferentially associated with filaments, accretion interfaces, and overdense regions. For the SIMBA realization at z = 0, Helmholtz decomposition shows that approximately 64% of the resolved velocity power is solenoidal and 36% compressive, giving an integrated ratio of about 1.8. The vorticity and nonlinear-source spectra strengthen toward low redshift, and exhibit organized multiscale behavior in both suites. The statistics further show intermittent vorticity, strong enstrophy growth, and scale-dependent correlations between the nonlinear rotational-compressive source and baryonic density fluctuations. Similar signatures in IllustrisTNG and SIMBA, despite different feedback prescriptions, indicate that these trends are robust features of nonlinear baryonic evolution. Although the available resolution does not establish fully developed turbulence, the results provide quantitative evidence that rotational motions are an important emergent component of cosmic-web dynamics and contribute to the multiscale organization of baryonic matter.
SN - 0004-637X
SN - 1538-4357
ER -