Shapes of Gas, Gravitational Potential, and Dark Matter in ΛCDM Clusters
TLDR
In this article, the shape of the gas in the Lambda CDM cosmology has been analyzed in the context of cosmological simulations of the LDM cosmology, and the authors found that the gas and potential shapes differ significantly at smaller radii.Abstract:
We present analysis of the three-dimensional shape of intracluster gas in clusters formed in cosmological simulations of the Lambda CDM cosmology and compare it to the shape of dark matter distribution and the shape of the overall isopotential surfaces. We find that in simulations with radiative cooling, star formation, and stellar feedback (CSF), intracluster gas outside the cluster core (r >= 0.1r(500)) is more spherical compared to non-radiative (NR) simulations, while in the core the gas in the CSF runs is moretriaxial and has a distinctly oblate shape. The latter reflects the ongoing cooling of gas, which settles into a thick oblate ellipsoid as it loses thermal energy. The shape of the gas in the inner regions of clusters can therefore be a useful diagnostic of gas cooling. We find that gas traces the shape of the underlying potential rather well outside the core, as expected in hydrostatic equilibrium. At smaller radii, however, the gas and potential shapes differ significantly. In the CSF runs, the difference reflects the fact that gas is partly rotationally supported. Interestingly, we find that in NR simulations the difference between gas and potential shape at small radii is due to random gas motions, which make the gas distribution more spherical than the equipotential surfaces. Finally, we use mock Chandra X-ray maps to show that the differences in shapes observed in a three-dimensional distribution of gas are discernible in the ellipticity of X-ray isophotes. Contrasting the ellipticities measured in simulated clusters against observations can therefore constrain the amount of cooling in the intracluster medium and the presence of random gas motions in cluster cores.read more
Citations
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Formation of Galaxy Clusters
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Clash: weak-lensing shear-and-magnification analysis of 20 galaxy clusters*
Keiichi Umetsu,Elinor Medezinski,Mario Nonino,Julian Merten,Marc Postman,Massimo Meneghetti,Massimo Meneghetti,Megan Donahue,Nicole G. Czakon,Alberto Molino,Stella Seitz,Daniel Gruen,Doron Lemze,Italo Balestra,Narciso Benítez,Andrea Biviano,Tom Broadhurst,Holland C. Ford,Claudio Grillo,Anton M. Koekemoer,Peter Melchior,Amata Mercurio,John Moustakas,Piero Rosati,Adi Zitrin +24 more
TL;DR: In this paper, a joint shear-and-magnification weak-lensing analysis of a sample of 16 X-ray-regular and 4 high magnification galaxy clusters at 0.19 ≾ z ≾ 0.69 was presented.
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On the accuracy of weak-lensing cluster mass reconstructions
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Combined strong and weak lensing analysis of 28 clusters from the Sloan Giant Arcs Survey
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Lensing and X-ray mass estimates of clusters (SIMULATION)
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TL;DR: In this paper, a comparison between weak-lensing (WL) and X-ray mass estimates of a sample of numerically simulated clusters is presented. But the results are limited to the 20 most massive objects at redshift z = 0.25 and Mvir > 5 x 10^{14} Msun h^{-1}.
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