Troubled cosmic flows: turbulence, enstrophy, and helicity from the assembly history of the intracluster medium

Vallés-Pérez, David; Planelles, S.; Quilis, Vicent

doi:10.1093/mnras/stab880

Cited by 17 publications

(10 citation statements)

References 103 publications

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“…We attribute the difference to the unavoidable presence of compressive turbulence, consistent with previous work (e.g. Miniati 2015;Vazza et al 2017;Vallés-Pérez et al 2021) . Furthermore, the turbulent anisotropy parameter shows the effects of substantial radial accretion (see Fig.…”

Section: Discussionsupporting

confidence: 89%

“…Alternatively, one can estimate the turbulent motions by interpolating the original 3-D velocity field in order to map the local mean field and to identify turbulent velocity fluctuations on scales smaller than the interpolation scale (Vazza et al 2009(Vazza et al , 2011a. As another alternative, a multi-scale iterative filtering approach has been implemented in, for example, Vazza et al (2012), Angelinelli et al (2020), Vallés-Pérez et al (2021. In the present work, we apply a simpler approach, that is by using a fixed scale filtering method, based on previous results by our group.…”

Section: Introductionmentioning

confidence: 99%

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Exploring the relation between turbulent velocity and density fluctuations in the stratified intracluster medium

Simonte

Vazza

Brighenti

et al. 2022

A&A

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Context. The dynamics of the intracluster medium (ICM) is affected by turbulence driven by several processes, such as mergers, accretion and feedback from active galactic nuclei. Aims. X-ray surface brightness fluctuations have been used to constrain turbulence in galaxy clusters. Here, we use simulations to further investigate the relation between gas density and turbulent velocity fluctuations, with a focus on the effect of the stratification of the ICM. Methods. In this work, we studied the turbulence driven by hierarchical accretion by analysing a sample of galaxy clusters simulated with the cosmological code ENZO. We used a fixed scale filtering approach to disentangle laminar from turbulent flows. Results. In dynamically perturbed galaxy clusters, we found a relation between the root mean square of density and velocity fluctuations, albeit with a different slope than previously reported. The Richardson number is a parameter that represents the ratio between turbulence and buoyancy, and we found that this variable has a strong dependence on the filtering scale. However, we could not detect any strong relation between the Richardson number and the logarithmic density fluctuations, in contrast to results by recent and more idealised simulations. In particular, we find a strong effect from radial accretion, which appears to be the main driver for the gas fluctuations. The ubiquitous radial bias in the dynamics of the ICM suggests that homogeneity and isotropy are not always valid assumptions, even if the turbulent spectra follow Kolmogorov's scaling. Finally, we find that the slope of the velocity and density spectra are independent of cluster-centric radii.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Exploring the relation between turbulent velocity and density fluctuations in the stratified intracluster medium

Simonte

Vazza

Brighenti

et al. 2022

A&A

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show abstract

“…Exploring gas azimuthal decomposition on 2-D mock X-ray (and SZ) images will be the next necessary step to accurately evaluate the efficiency of such a technique on data observations by considering observational effects such as finite angular resolution, noise, etc. This approach might require high angular resolution (similarly to Vallés-Pérez et al 2021;Capalbo et al 2021), and could be a powerful tool to highlight patterns in current and future observations of the cosmic gas at the peripheries of galaxy clusters (Tchernin et al 2016;Barcons et al 2017;XRISM Science Team 2020;CHEX-MATE Collaboration et al 2021;Simionescu et al 2021).…”

Section: Discussionmentioning

confidence: 99%

“…Cluster peripheries are thus crucial places to probe the transition between hot and warm gas, and to probe the complex dynamics of infalling WHIM gas. In fact, this is in these regions that gas is expected to flow from filaments into clusters, with turbulent motions (Rost et al 2021;Vallés-Pérez et al 2021), and where accretion shocks might arise (Shi et al 2020;Zhang et al 2020Zhang et al , 2021bZhu et al 2021b). Following these findings on the radial gas properties, we focus in the rest of the paper our exploration of the azimuthal gas distribution in cluster environment concentrating on two main gas phases in two different radial apertures: hot medium up to 1 R 200 and WHIM from 1 to 2R 200 .…”

Section: Radial Gas Properties Summarymentioning

confidence: 99%

Gas distribution from clusters to filaments in IllustrisTNG

Gouin,

Gallo,

Aghanim

2022

Preprint

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Matter distribution in the environment of galaxy clusters, from their cores to their connected cosmic filaments, must be in principle related to the underlying cluster physics and it evolutionary state. We aim to investigate how radial and azimuthal distribution of gas is affected by cluster environments, and how it can be related to cluster mass assembly history. Radial physical properties of gas (velocity, temperature, and density) is first analysed around 415 galaxy cluster environments from IllustrisTNG simulation at z = 0. Whereas hot plasma is virialised inside clusters (< R200), the dynamics of warm hot inter-galactic medium (WHIM) can be separated in two regimes: accumulating and slowly infalling gas at cluster peripheries (∼ R200) and fast infalling motions outside clusters (> 1.5R200). The azimuthal distribution of dark matter (DM), hot and warm gas phases is secondly statistically probed by decomposing their 2-D distribution in harmonic space. Inside clusters, the azimuthal symmetries of DM and hot gas are well tracing cluster structural properties, such as their center offsets, substructure fractions and elliptical shapes. Beyond cluster virialised regions, we found that WHIM gas follows the azimuthal distribution of DM by tracing cosmic filament patterns. Azimuthal symmetries of hot and warm gas distribution is finally shown to be imprints of cluster mass assembly history, by strongly correlating with the formation time, mass accretion rate, and dynamical state of clusters. Azimuthal mode decomposition of 2-D gas distribution is a promising probe to assess the 3-D physical and dynamical cluster properties up to their connected cosmic filaments.

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“…All the three simulations are performed at magnetic Prandtl number Pm = Rm/Re = 1, where Rm and Re are the magnetic and fluid Reynolds numbers, respectively. Recent cosmological simulations of hierarchical structure formation including the formation of galaxy clusters show that turbulence in the cluster core is dominated by solenoidal modes [33][34][35][36]. Accordingly, and to maximize the efficiency of the fluctuation dynamo, we use only solenoidal modes (i.e., ∇ • F = 0) for the turbulent driving.…”

Section: Summary Of Magnetohydrodynamic (Mhd) Simulationsmentioning

confidence: 99%

Properties of Polarized Synchrotron Emission from Fluctuation Dynamo Action—II. Effects of Turbulence Driving in the ICM and Beam Smoothing

Basu

Sur

2021

Galaxies

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Polarized synchrotron emission from the radio halos of diffuse intracluster medium (ICM) in galaxy clusters are yet to be observed. To investigate the expected polarization in the ICM, we use high resolution (1 kpc) magnetohydrodynamic simulations of fluctuation dynamos, which produces intermittent magnetic field structures, for varying scales of turbulent driving (lf) to generate synthetic observations of the polarized emission. We focus on how the inferred diffuse polarized emission for different lf is affected due to smoothing by a finite telescope resolution. The mean fractional polarization ⟨p⟩ vary as ⟨p⟩∝lf1/2 with ⟨p⟩>20% for lf≳60 kpc, at frequencies ν>4GHz. Faraday depolarization at ν<3 GHz leads to deviation from this relation, and in combination with beam depolarization, filamentary polarized structures are completely erased, reducing ⟨p⟩ to below 5% level at ν≲1 GHz. Smoothing on scales up to 30 kpc reduces ⟨p⟩ above 4 GHz by at most a factor of 2 compared to that expected at 1 kpc resolution of the simulations, especially for lf≳100 kpc, while at ν<3 GHz, ⟨p⟩ is reduced by a factor of more than 5 for lf≳100 kpc, and by more than 10 for lf≲100 kpc. Our results suggest that observational estimates of, or constrain on, ⟨p⟩ at ν≳4 GHz could be used as an indicator of the turbulent driving scale in the ICM.

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Troubled cosmic flows: turbulence, enstrophy, and helicity from the assembly history of the intracluster medium

Cited by 17 publications

References 103 publications

Exploring the relation between turbulent velocity and density fluctuations in the stratified intracluster medium

Exploring the relation between turbulent velocity and density fluctuations in the stratified intracluster medium

Gas distribution from clusters to filaments in IllustrisTNG

Properties of Polarized Synchrotron Emission from Fluctuation Dynamo Action—II. Effects of Turbulence Driving in the ICM and Beam Smoothing

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