Cloud Atlas: Navigating the Multiphase Landscape of Tempestuous Galactic Winds

TL;DR

This paper investigates the multiphase structure of galactic winds through 3D magnetohydrodynamical simulations, revealing how turbulence, cloud formation, and magnetic fields influence galaxy evolution models.

Contribution

It provides new insights into the origin, properties, and modeling of cool clouds in galactic winds, bridging small-scale simulations with larger, realistic galaxy models.

Findings

Cloud sizes follow a power law distribution.

Turbulent radiative mixing layers explain mass growth.

Magnetic fields have minor influence on cloud support.

Abstract

Galaxies comprise intricate networks of interdependent processes which together govern their evolution. Central among these are the multiplicity of feedback channels, which remain incompletely understood. One outstanding problem is the understanding and modeling of the multiphase nature of galactic winds, which play a crucial role in galaxy formation and evolution. We present the results of three dimensional magnetohydrodynamical tall box interstellar medium patch simulations with clustered supernova driven outflows. Fragmentation of the interstellar medium during superbubble breakout seeds the resulting hot outflow with a population of cool clouds. We focus on analyzing and modeling the origin and properties of these clouds. Their presence induces large scale turbulence, which in turn leads to complex cloud morphologies. Cloud sizes are well described by a power law distribution and mass growth rates can be modelled using turbulent radiative mixing layer theory. Turbulence provides significant pressure support in the clouds, while magnetic fields only play a minor role. We conclude that many of the physical insights and analytic scalings derived from idealized small scale simulations translate well to larger scale, more realistic turbulent magnetized winds, thus paving a path towards their necessary yet challenging inclusion in global-scale galaxy models.