English

Survival of higher overdensity cold gas in a turbulent, multiphase medium

Astrophysics of Galaxies 2025-11-17 v2 Cosmology and Nongalactic Astrophysics

Abstract

Cold gas clouds embedded in a hot, turbulent medium are expected to be short-lived due to disruptive hydrodynamic instabilities. However, radiative cooling might allow such clouds to survive and grow. We present 3D \texttt{Athena++} simulations of clouds with a density contrast of χ=1000\chi = 1000, exploring turbulent Mach numbers M(0.25,0.75)\mathcal{M}\in (0.25, 0.75) and cloud radii chosen to span cooling-to-crushing ratios α[0.001,10]\alpha \in [0.001, 10]. We find a shift in the survival boundary, with cloud survival occurring only when the cooling-to-cloud-crushing ratio (tcool,mix/tcct_{\text{cool,mix}} / t_{\text{cc}}) 0.01\lesssim 0.01, which is lower than the expected boundary of 1\sim 1. This result shows that it is more difficult for higher over-density cold clouds to survive in a turbulent, hot medium, and suggests another `survival criterion'.

Keywords

Cite

@article{arxiv.2507.20962,
  title  = {Survival of higher overdensity cold gas in a turbulent, multiphase medium},
  author = {Ashwin Vergis George and Hitesh Kishore Das and Max Gronke},
  journal= {arXiv preprint arXiv:2507.20962},
  year   = {2025}
}