Characterizing gravitational instability in turbulent multi-component galactic discs
arXiv:1502.05583 · doi:10.1093/mnras/stv440
Abstract
Gravitational instabilities play an important role in galaxy evolution and in shaping the interstellar medium (ISM). The ISM is observed to be highly turbulent, meaning that observables like the gas surface density and velocity dispersion depend on the size of the region over which they are measured. In this work we investigate, using simulations of Milky Way-like disc galaxies with a resolution of pc, the nature of turbulence in the ISM and how this affects the gravitational stability of galaxies. By accounting for the measured average turbulent scalings of the density and velocity fields in the stability analysis, we can more robustly characterize the average level of stability of the galaxies as a function of scale, and in a straightforward manner identify scales prone to fragmentation. Furthermore, we find that the stability of a disc with feedback-driven turbulence can be well described by a "Toomre-like" stability criterion on all scales, whereas the classical can formally lose its meaning on small scales if violent disc instabilities occur in models lacking pressure support from stellar feedback.
11 pages, 5 figures, submitted to MNRAS
References in corpus (19)
- Theory of Star Formation
- The Statistics of Supersonic Isothermal Turbulence
- The Resolved Properties of Extragalactic Giant Molecular Clouds
- What is Driving the HI Velocity Dispersion?
- Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
- Kinemetry of SINS High-Redshift Star-Forming Galaxies: Distinguishing Rotating Disks from Major Mergers
- A simple multigrid scheme for solving the Poisson equation with arbitrary domain boundaries
- Unstable disks at high redshift: Evidence for smooth accretion in galaxy formation
- Large scale galactic turbulence: can self-gravity drive the observed HI velocity dispersions?
- Is the Scaling of Supersonic Turbulence Universal?
- Scaling Relations of Compressible MHD Turbulence
- Discreteness Effects in Lambda Cold Dark Matter Simulations: A Wavelet-Statistical View
- Larson's scaling laws, and the gravitational instability of clumpy discs at high redshift
- Power spectrum of HI intensity fluctuations in DDO 210
- The fractal dimension of star-forming regions at different spatial scales in M33
- HI power spectrum of the spiral galaxy NGC628
- The effect of ISM turbulence on the gravitational instability of galactic discs
- Probing interstellar turbulence in spiral galaxies using HI power spectrum analysis
- Turbulence measurements from HI absorption spectra