Towards mapping turbulence in the intra-cluster medium -- I. Sample variance in spatially-resolved X-ray line diagnostics

Clerc, N.; Cucchetti, E.; Pointecouteau, E.; Peille, P.

doi:10.48550/arxiv.1904.06248

Cited by 1 publication

(1 citation statement)

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“…Moreover, indirect hints of the presence of residual kinetic energy associated with random gas motions in the intracluster medium comes from the observational evidence of diffuse radio emission connected with cluster undergoing mergers (and likely powered by the dissipation of turbulent motions via Fermi-like mechanisms, see van Weeren et al 2019 for a recent review) and from the observed correlation between X-ray surface brightness fluctuations and radio power Eckert et al 2017) which suggests a dynamical link between perturbed X-ray morphologies and residual gas motions. Unfortunately, for the direct ICM velocity measurements we need to wait for next generation X-ray spectrometers (Biffi et al 2013;Roncarelli et al 2018;ZuHone et al 2018;Simionescu et al 2019;Cucchetti et al 2019;Clerc et al 2019) which might obtain such measures in the external regions of (a few) clusters, such as those obtained by Hitomi for the core of the Perseus cluster (Hitomi Collaboration et al 2016).…”

Section: Introductionmentioning

confidence: 99%

The Three Hundred Project: Correcting for the hydrostatic-equilibrium mass bias in X-ray and SZ surveys

Ansarifard

Rasia

Biffi

et al. 2020

A&A

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Accurate and precise measurements of masses of galaxy clusters are key to derive robust constraints on cosmological parameters. Rising evidence from observations, however, confirms that X-ray masses, obtained under the assumption of hydrostatic equilibrium, might be underestimated, as previously predicted by cosmological simulations. We analyse more than 300 simulated massive clusters, from 'The Three Hundred Project', and investigate the connection between mass bias and several diagnostics extracted from synthetic X-ray images of these simulated clusters. We find that the azimuthal scatter measured in 12 sectors of the X-ray flux maps is a statistically significant indication of the presence of an intrinsic (i.e. 3D) clumpy gas distribution. We verify that a robust correction to the hydrostatic mass bias can be inferred when estimates of the gas inhomogeneity from X-ray maps (such as the azimuthal scatter or the gas ellipticity) are combined with the asymptotic external slope of the gas density or pressure profiles, which can be respectively derived from X-ray and millimetric (Sunyaev-Zeldovich effect) observations. We also obtain that mass measurements based on either gas density and temperature or gas density and pressure result in similar distributions of the mass bias. In both cases, we provide corrections that help reduce both the dispersion and skewness of the mass bias distribution. These are effective even when irregular clusters are included leading to interesting implications for the modelling and correction of hydrostatic mass bias in cosmological analyses of current and future X-ray and SZ cluster surveys.

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