Shattering and growth of cold clouds in galaxy clusters: the role of radiative cooling, magnetic fields and thermal conduction

Abstract

In galaxy clusters, the hot intracluster medium (ICM) can develop a striking multi-phase structure around the brightest cluster galaxy. Much work has been done on understanding the origin of this central nebula, but less work has studied its eventual fate after the originally filamentary structure is broken into individual cold clumps. In this paper we perform a suite of 30 (magneto-)hydrodynamical simulations of kpc-scale cold clouds with typical parameters as found by galaxy cluster simulations, to understand whether clouds are mixed back into the hot ICM or can persist. We investigate the effects of radiative cooling, small-scale heating, magnetic fields, and (anisotropic) thermal conduction on the long-term evolution of clouds. We find that filament fragments cool on timescales shorter than the crushing timescale, fall out of pressure equilibrium with the hot medium, and shatter, forming smaller clumplets. These act as nucleation sites for further condensation, and mixing via Kelvin-Helmholtz instability, causing cold gas mass to double within 75 Myr. Cloud growth depends on density, as well as on local heating processes, which determine whether clouds undergo ablation- or shattering-driven evolution. Magnetic fields slow down but don't prevent cloud growth, with the evolution of both cold and warm phase sensitive to the field topology. Counter-intuitively, anisotropic thermal conduction increases the cold gas growth rate compared to non-conductive clouds, leading to larger amounts of warm phase as well. We conclude that dense clumps on scales of $500$ pc or more cannot be ignored when studying the long-term cooling flow evolution of galaxy clusters.

21 pages, 26 figures, Accepted for Publication in MNRAS

References in corpus (19)

• Heating Hot Atmospheres with Active Galactic Nuclei
• A High Order Godunov Scheme with Constrained Transport and Adaptive Mesh Refinement for Astrophysical MHD
• Draping of Cluster Magnetic Fields over Bullets and Bubbles -- Morphology and Dynamic Effects
• Magnetized Gas Clouds can Survive Acceleration by a Hot Wind
• The Launching of Cold Clouds by Galaxy Outflows I: Hydrodynamic Interactions with Radiative Cooling
• Cold molecular gas in the Perseus cluster core - Association with X-ray cavity, Halpha filaments and cooling flow -
• Magnetic support of the optical emission line filaments in NGC 1275
• Efficiency of gas cooling and accretion at the disc-corona interface
• ALMA observations of massive molecular gas filaments encasing radio bubbles in the Phoenix cluster
• A uniform metallicity in the outskirts of massive, nearby galaxy clusters
• Conduction and the Star-Formation Threshold in Brightest Cluster Galaxies
• Filamentary Star Formation in NGC 1275
• The evolution of interstellar clouds in a streaming hot plasma including heat conduction
• Shaping the X-ray spectrum of galaxy clusters with AGN feedback and turbulence
• Characterization of ICM Temperature Distributions of 62 Galaxy Clusters with XMM-Newton
• The Dust and Molecular Gas in the Brightest Cluster Galaxy in MACS 1931.8-2635
• Constraining the Magnetic Field of the Smith High Velocity Cloud using Faraday rotation
• WISDOM project -- VIII. Multi-scale feedback cycles in the brightest cluster galaxy NGC 0708
• AGN feedback in the FR II galaxy 3C 220.1

Cited by in corpus (2)

• The Circumgalactic Medium of Milky Way-like Galaxies in the TNG50 Simulation -- II: Cold, Dense Gas Clouds and High-Velocity Cloud Analogs
• A Dynamical Test for Cooling-Induced Entrainment in a Runaway Supermassive Black Hole Tail