Dynamics of Gaseous Disks in a Non-axisymmetric Dark Halo

TL;DR

This study uses high-resolution hydrodynamical simulations to explore how non-axisymmetric dark halos influence the formation and evolution of spiral structures in galactic gaseous disks, revealing long-lived, multi-armed spirals with complex kinematics.

Contribution

It provides detailed numerical analysis of spiral pattern formation in gaseous disks within triaxial dark halos, highlighting the impact of various halo and disk parameters on spiral morphology and dynamics.

Findings

Long-lived, two-armed spiral patterns form across various parameters.

Spiral structures are global with 2-3 turns, depending on model specifics.

Spiral pattern rotation is slow and varies quasi-periodically.

Abstract

The dynamics of a galactic disk in a non-axisymmetric (triaxial) dark halo is studied in detail using high-resolution, numerical, hydrodynamical models. A long-lived, two-armed spiral pattern is generated for a wide range of parameters. The spiral structure is global, and the number of turns can be two or three, depending on the model parameters. The morphology and kinematics of the spiral pattern are studied as functions of the halo and disk parameters. The spiral structure rotates slowly, and its angular velocity varies quasi-periodically. Models with differing relative halo masses, halo semi-axis ratios, distributions of matter in the disk, Mach numbers in the gaseous component, and angular rotational velocities of their halos are considered.