Thermal instability in rotating galactic coronae

Abstract

The thermal stability of rotating, stratified, unmagnetized atmospheres is studied by means of linear-perturbation analysis, finding stability, overstability or instability, depending on the properties of the gas distribution, but also on the nature of the perturbations. In the relevant case of distributions with outward-increasing specific entropy and angular momentum, axisymmetric perturbations grow exponentially, unless their wavelength is short enough that they are damped by thermal conduction; non-axisymmetric perturbations typically undergo overstable oscillations in the limit of zero conductivity, but are effectively stabilized by thermal conduction, provided rotation is differential. To the extent that the studied models are representative of the poorly constrained hot atmospheres of disc galaxies, these results imply that blob-like, cool overdensities are unlikely to grow in galactic coronae, suggesting an external origin for the high-velocity clouds of the Milky Way.

18 pages, 5 figures. Accepted for publication in MNRAS

References in corpus (9)

• Buoyancy Instabilities in Weakly Magnetized Low Collisionality Plasmas
• Seeding the formation of cold gaseous clouds in Milky Way size halos
• Where are the ``Missing'' Galactic Baryons?
• Do high-velocity clouds form by thermal instability?
• Hot gas halos around disk galaxies: Confronting cosmological simulations with observations
• Redistributing hot gas around galaxies: do cool clouds signal a solution to the overcooling problem?
• Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos
• On Differential Rotation and Convection in the Sun
• Are galactic coronae thermally unstable?

Cited by in corpus (21)

• Supernova-driven gas accretion in the Milky Way
• Galactic fountains and the rotation of disc-galaxy coronae
• Gas Condensation in the Galactic Halo
• HALOGAS: the properties of extraplanar HI in disc galaxies
• Estimating gas accretion in disc galaxies using the Kennicutt-Schmidt law
• The effects of the cluster environment on the galaxy mass-size relation in MACSJ J1206.2-0847
• On the origin of the warm-hot absorbers in the Milky Way's halo
• Intermediate- and high-velocity clouds in the Milky Way II: evidence for a Galactic fountain with collimated outflows and diffuse inflows
• Models of rotating coronae
• Gas rotation in galaxy clusters: signatures and detectability in X-rays
• Fountain-driven gas accretion feeding star formation over the disc of NGC 2403
• The effect of rotation on the thermal instability of stratified galactic atmospheres - I. Local analysis
• The effect of rotation on the thermal instability of stratified galactic atmospheres - II. The formation of High Velocity Clouds
• Gas accretion in Milky Way-like galaxies: temporal and radial dependencies
• On the nature of local instabilities in rotating galactic coronae and cool cores of galaxy clusters
• HI within and around observed and simulated galaxy discs -- Comparing MeerKAT observations with mock data from TNG50 and FIRE-2
• Thermal stability of a weakly magnetized rotating plasma
• Removal and mixing of the coronal gas from satellites in galaxy groups: cooling the intragoup gas
• Electromagnetic thermal instability with momentum and energy exchange between electrons and ions in galaxy clusters
• Magnetorotational instability in cool cores of galaxy clusters
• Understanding the Baryon Cycle: Fueling Star Formation via Inflows in Milky Way-like Galaxies