Strength in numbers: A multiphase wind model with multiple cloud populations

Abstract

Galactic outflows have a multiphase nature making them challenging to model analytically. Many previous studies have tried to produce models that come closer to reality. In this work, we continue these efforts and describe the interaction of the hot wind fluid with multiple cold cloud populations, with their number density determined by different probability density functions. To do so, we introduced realistic cloud-wind interaction source terms and a time-varying cooling area. We find that the model reproduces well results from small-scale hydrodynamic simulations, but exhibits a general destructive behavior both for a single cloud population as well as multiple ones. We show that including multiple cloud populations can alter the evolution of the wind drastically. We also compare our model to observations and show that the differential acceleration of multiple clouds can lead to a non-negligible velocity `dispersion' relevant for down-the-barrel studies. Furthermore, we compute the emitted cooling surface brightness and find it generally too faint to explain observed Lyman-$\alpha$ halos.

17 pages, 15 figures, to be published in Monthly Notices of the Royal Astronomical Society

References in corpus (14)

• Array Programming with NumPy
• The Circumgalactic Medium
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• CMasher: Scientific colormaps for making accessible, informative and 'cmashing' plots
• Magnetized Gas Clouds can Survive Acceleration by a Hot Wind
• The Launching of Cold Clouds by Galaxy Outflows I: Hydrodynamic Interactions with Radiative Cooling
• Hydrodynamical Coupling of Mass and Momentum in Multiphase Galactic Winds
• Efficiency of gas cooling and accretion at the disc-corona interface
• A Review of Recent Observations of Galactic Winds Driven by Star Formation
• The Magnetohydrodynamics of Shock-Cloud Interaction in Three Dimensions
• Surface Brightness Profile of Lyman-$\alpha$ Halos out to 320 kpc in HETDEX
• Numerical simulations of shocks encountering clumpy regions
• Cloud coalescence: a dynamical instability affecting multiphase environments
• Magnetized High Velocity Clouds in the Galactic Halo: A New Distance Constraint

Cited by in corpus (5)

• Physical Origins of Outflowing Cold Clouds in Local Star-forming Dwarf Galaxies
• Fading in the Flow: Suppression of cold gas growth in expanding galactic outflows
• The GECKOS Survey: Resolved, multiphase observations of mass-loading and gas density in the galactic wind of NGC 4666
• Imladris: a detailed and flexible model for galaxy simulations with individual stars
• Modeling Emission-Line Surface Brightness in a Multiphase Galactic Wind: An O VI Case Study