Radiative turbulent mixing layers at high Mach numbers

Abstract

Radiative turbulent mixing layers (TMLs) are ubiquitous in astrophysical environments, e.g., the circumgalactic medium (CGM), and are triggered by the shear velocity at interfaces between different gas phases. To understand the shear velocity dependence of TMLs, we perform a set of 3D hydrodynamic simulations with an emphasis on the TML properties at high Mach numbers $\mathcal{M}$. Since the shear velocity in mixing regions is limited by the local sound speed of mixed gas, high-Mach number TMLs develop into a two-zone structure: a Mach number-independent mixing zone traced by significant cooling and mixing, plus a turbulent zone with large velocity dispersions which expands with greater $\mathcal{M}$. Low-Mach number TMLs do not have distinguishable mixing and turbulent zones. The radiative cooling of TMLs at low and high Mach numbers is predominantly balanced by enthalpy consumption and turbulent dissipation respectively. Both the TML surface brightness and column densities of intermediate-temperature ions (e.g., O VI) scale as $\propto {\mathcal{M}}^{0.5}$ at $\mathcal{M}\lesssim 1$, but reach saturation ($\propto {\mathcal{M}}^0$) at $\mathcal{M}\gtrsim 1$. Inflow velocities and hot gas entrainment into TMLs are substantially suppressed at high Mach numbers, and strong turbulent dissipation drives the evaporation of cold gas. This is in contrast to low-Mach number TMLs where the inflow velocities and hot gas entrainment are enhanced with greater $\mathcal{M}$, and cold gas mass increases due to the condensation of entrained hot gas.

16 pages, 17 figures, 4 tables, revised to match accepted MNRAS version

References in corpus (35)

• The NumPy array: a structure for efficient numerical computation
• Cold streams in early massive hot haloes as the main mode of galaxy formation
• The Circumgalactic Medium
• The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium
• The COS-Halos Survey: Metallicities in the Low-Redshift Circumgalactic Medium
• Characterizing the Circumgalactic Medium of Nearby Galaxies with HST/COS and HST/STIS Absorption-Line Spectroscopy
• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• The Launching of Cold Clouds by Galaxy Outflows I: Hydrodynamic Interactions with Radiative Cooling
• Properties of the Circumgalactic Medium in Cosmic Ray-Dominated Galaxy Halos
• How AGN Jets Heat the Intracluster Medium -- Insights from Hydrodynamic Simulations
• On the possible environmental effect in distributing heavy elements beyond individual gaseous halos
• Multiphase Gas and the Fractal Nature of Radiative Turbulent Mixing Layers
• The Physical Nature of Starburst-Driven Galactic Outflows
• Hydrodynamical Coupling of Mass and Momentum in Multiphase Galactic Winds
• The Structure of Multiphase Galactic Winds
• Virialization of the inner CGM in the FIRE simulations and implications for galaxy discs, star formation and feedback
• Interaction of a cold cloud with a hot wind: the regimes of cloud growth and destruction and the impact of magnetic fields
• The Properties of Low Redshift Intergalactic O VI Absorbers Determined from High S/N Observations of 14 QSOs with the Cosmic Origins Spectrograph
• Evidence for a Massive, Extended Circumgalactic Medium Around the Andromeda Galaxy
• On the Survival of Cool Clouds in the Circum-Galactic Medium
• The effects of cosmic rays on the formation of Milky Way-mass galaxies in a cosmological context
• Survival and mass growth of cold gas in a turbulent, multiphase medium
• Instability of Supersonic Cold Streams Feeding Galaxies IV: Survival of Radiatively Cooling Streams
• Radiative Mixing Layers: Insights from Turbulent Combustion
• Growth and structure of multiphase gas in the cloud-crushing problem with cooling
• Numerical Study of Turbulent Mixing Layers with Non-Equilibrium Ionization Calculations
• Cosmic-Ray Driven Outflows to Mpc Scales from $L_{\ast }$ Galaxies
• The Survival of Multiphase Dusty Clouds in Hot Winds
• How Do Supernovae Impact the Circumgalactic Medium? I. Large-Scale Fountains Around a Milky Way-Like Galaxy
• Shock-multicloud interactions in galactic outflows -- II. Radiative fractal clouds and cold gas thermodynamics
• Interaction of Cosmic Rays with Cold Clouds in Galactic Halos
• The in situ formation of molecular and warm ionised gas triggered by hot outflows
• Virial shocks are suppressed in cosmic ray-dominated galaxy halos
• The Warm Gas in the MW: A Kinematical Model
• The high-velocity clouds above the disk of the outer Milky Way: misty precipitating gas in a region roiled by stellar streams

Cited by in corpus (12)

• Figuring Out Gas & Galaxies In Enzo (FOGGIE) VI: The Circumgalactic Medium of $L^{\ast }$ Galaxies is Supported in an Emergent, Non-Hydrostatic Equilibrium
• Cooling driven coagulation
• Scientific Objectives of the Hot Universe Baryon Surveyor (HUBS) Mission
• The Anatomy of a Turbulent Radiative Mixing Layer: Insights from an Analytic Model with Turbulent Conduction and Viscosity
• Simulations of Weakly Magnetized Turbulent Mixing Layers
• FEASTS Combined with Interferometry. III. The Low Column Density HI Around M51 and Possibility of Turbulent-mixing Gas Accretion
• Strength in numbers: A multiphase wind model with multiple cloud populations
• Stability and Ly$\alpha$ emission of Cold Stream in the Circumgalactic Medium: impact of magnetic fields and thermal conduction
• Fading in the Flow: Suppression of cold gas growth in expanding galactic outflows
• Neural Infalling Cloud Equations (NICE): Increasing the Efficacy of Subgrid Models and Scientific Equation Discovery using Neural ODEs and Symbolic Regression
• A Dynamical Test for Cooling-Induced Entrainment in a Runaway Supermassive Black Hole Tail
• Recent Developments on the HI Gas of Low-Redshift Galaxies Seen by the 21cm Emission Lines