Precipitation possible: turbulence-driven thermal instability with constrained entropy profiles

Fuente: arXiv
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Autori principali: Wibking, Benjamin D., Voit, G. Mark, O'Shea, Brian W.
Natura: Preprint
Pubblicazione: 2024
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author Wibking, Benjamin D.
Voit, G. Mark
O'Shea, Brian W.
author_facet Wibking, Benjamin D.
Voit, G. Mark
O'Shea, Brian W.
contents Precipitation of cold gas due to thermal instability in both galaxy clusters and the circumgalactic medium may regulate AGN feedback. We investigate thermal instability in idealized simulations of the circumgalactic medium with a parameter study of over 600 three-dimensional hydrodynamic simulations of stratified turbulence with cooling, each evolved for 10 Gyr. The entropy profiles are maintained in a steady state via an idealized `thermostat' process, consistent with galaxy cluster entropy profiles. In the presence of external turbulent driving, we find cold gas precipitates, with a strong dependence whether the turbulent driving mechanism is solenoidal, compressive, or purely vertical. In the purely-vertical turbulent driving regime, we find that significant cold gas may form when the cooling time to free-fall time $t_{\rm cool} / t_{\text{ff}} \lesssim 5$. Our simulations with a ratio of $t_{\rm cool} / t_{\text{ff}} \sim 10$ do not precipitate under any circumstances, perhaps because the thermostat mechanism we use maintains a significant non-zero entropy gradient.
format Preprint
id arxiv_https___arxiv_org_abs_2410_03886
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Precipitation possible: turbulence-driven thermal instability with constrained entropy profiles
Wibking, Benjamin D.
Voit, G. Mark
O'Shea, Brian W.
Astrophysics of Galaxies
Precipitation of cold gas due to thermal instability in both galaxy clusters and the circumgalactic medium may regulate AGN feedback. We investigate thermal instability in idealized simulations of the circumgalactic medium with a parameter study of over 600 three-dimensional hydrodynamic simulations of stratified turbulence with cooling, each evolved for 10 Gyr. The entropy profiles are maintained in a steady state via an idealized `thermostat' process, consistent with galaxy cluster entropy profiles. In the presence of external turbulent driving, we find cold gas precipitates, with a strong dependence whether the turbulent driving mechanism is solenoidal, compressive, or purely vertical. In the purely-vertical turbulent driving regime, we find that significant cold gas may form when the cooling time to free-fall time $t_{\rm cool} / t_{\text{ff}} \lesssim 5$. Our simulations with a ratio of $t_{\rm cool} / t_{\text{ff}} \sim 10$ do not precipitate under any circumstances, perhaps because the thermostat mechanism we use maintains a significant non-zero entropy gradient.
title Precipitation possible: turbulence-driven thermal instability with constrained entropy profiles
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2410.03886