Weighing Galaxy Clusters With Gas. Ii. On the Origin of Hydrostatic Mass Bias in Λcdm Galaxy Clusters

Nelson, Keith E.; Lau, Erwin T.; Nagai, Daisuke; Rudd, Douglas H.; Yu, Li

doi:10.1088/0004-637x/782/2/107

Cited by 153 publications

(172 citation statements)

References 34 publications

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“…We analyze mock Chandra observations of massive galaxy clusters extracted from the Omega500 simulation (Nelson et al 2014). Below, we briefly summarize the main elements of the Omega500 simulation and mock Chandra observations of simulated clusters, and refer the readers to Nelson et al (2014) and Nagai et al (2007), respectively, for further details.…”

Section: Simulationsmentioning

confidence: 99%

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Testing for X-Ray–SZ Differences and Redshift Evolution in the X-Ray Morphology of Galaxy Clusters

Nurgaliev

McDonald

Benson

et al. 2017

ApJ

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We present a quantitative study of the X-ray morphology of galaxy clusters, as a function of their detection method and redshift. We analyze two separate samples of galaxy clusters: a sample of 36 clusters at z 0.35 0.9 < < selected in the X-ray with the ROSAT PSPC 400 deg 2 survey, and a sample of 90 clusters at z 0.25 1.2 < < selected via the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope. Clusters from both samples have similar-quality Chandra observations, which allow us to quantify their X-ray morphologies via two distinct methods: centroid shifts (w) and photon asymmetry (A phot ). The latter technique provides nearly unbiased morphology estimates for clusters spanning a broad range of redshift and data quality. We further compare the X-ray morphologies of X-ray-and SZ-selected clusters with those of simulated clusters. We do not find a statistically significant difference in the measured X-ray morphology of X-ray and SZ-selected clusters over the redshift range probed by these samples, suggesting that the two are probing similar populations of clusters. We find that the X-ray morphologies of simulated clusters are statistically indistinguishable from those of X-ray-or SZ-selected clusters, implying that the most important physics for dictating the large-scale gas morphology (outside of the core) is well-approximated in these simulations. Finally, we find no statistically significant redshift evolution in the X-ray morphology (both for observed and simulated clusters), over the range of z 0.3 to z 1 , seemingly in contradiction with the redshift-dependent halo merger rate predicted by simulations.

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Section: Simulationsmentioning

confidence: 99%

“…Below, we briefly summarize the main elements of the Omega500 simulation and mock Chandra observations of simulated clusters, and refer the readers to Nelson et al (2014) and Nagai et al (2007), respectively, for further details.…”

Section: Simulationsmentioning

confidence: 99%

Testing for X-Ray–SZ Differences and Redshift Evolution in the X-Ray Morphology of Galaxy Clusters

Nurgaliev

McDonald

Benson

et al. 2017

ApJ

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“…Nelson et al 2014). We next investigate to what degree the thermal pressure alone counteracts gravity in our simulations.…”

Section: Hydrostatic Mass and Deviationsmentioning

confidence: 99%

“…In contrast to uniform high resolution simulations with fully developed turbulence (Miniati & Beresnyak 2015), we can focus on thermal effects here inside the outer infall region. We follow Nelson et al (2014) and define the thermal (or hydrostatic) mass as…”

Section: Hydrostatic Mass and Deviationsmentioning

confidence: 99%

Rhapsody-G simulations I: the cool cores, hot gas and stellar content of massive galaxy clusters

Hahn

Martizzi

et al. 2017

Mon. Not. R. Astron. Soc.

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We present the Rhapsody-G suite of cosmological hydrodynamic AMR zoom simulations of ten massive galaxy clusters at the M vir ∼ 10 15 M scale. These simulations include cooling and sub-resolution models for star formation and stellar and supermassive black hole feedback. The sample is selected to capture the whole gamut of assembly histories that produce clusters of similar final mass. We present an overview of the successes and shortcomings of such simulations in reproducing both the stellar properties of galaxies as well as properties of the hot plasma in clusters. In our simulations, a long-lived cool-core/non-cool core dichotomy arises naturally, and the emergence of non-cool cores is related to low angular momentum major mergers. Nevertheless, the cool-core clusters exhibit a low central entropy compared to observations, which cannot be alleviated by thermal AGN feedback. For cluster scaling relations we find that the simulations match well the M 500 − Y 500 scaling of Planck SZ clusters but deviate somewhat from the observed X-ray luminosity and temperature scaling relations in the sense of being slightly too bright and too cool at fixed mass, respectively. Stars are produced at an efficiency consistent with abundance matching constraints and central galaxies have star formation rates consistent with recent observations. While our simulations thus match various key properties remarkably well, we conclude that the shortcomings strongly suggest an important role for non-thermal processes (through feedback or otherwise) or thermal conduction in shaping the intra-cluster medium.

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“…In the outskirts of galaxy clusters, the assumption of hydrostatic equilibrium may break down due to turbulence from infalling groups and IGM streams (Zinger et al 2016;Nelson et al 2014;Nagai et al 2007). The kinetic energy from the turbulent motions provides additional support against gravity and can lead to 10-30% uncertainty in the cluster mass estimates.…”

Section: Absorbers As Tracers Of Turbulent Gas Motionsmentioning

confidence: 99%

Lyα Absorbers and the Coma Cluster

Yoon

Putman

2017

ApJ

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The spatial and kinematic distribution of warm gas in and around the Coma Cluster is presented through observations of Lyα absorbers using background QSOs. Updates to the Lyα absorber distribution found in Yoon et al. (2012) for the Virgo Cluster are also presented. At 0.2-2.0R vir of Coma we identify 14 Lyα absorbers (N HI = 10 12.8−15.9 cm −2 ) towards 5 sightlines and no Lyα absorbers along 3 sightlines within 3σ vcoma . For both Coma and Virgo, most Lyα absorbers are found outside the virial radius or beyond 1σ v consistent with them largely representing the infalling intergalactic medium. The few exceptions in the central regions can be associated with galaxies. The Lyα absorbers avoid the hot ICM, consistent with the infalling gas being shock-heated within the cluster. The massive dark matter halos of clusters do not show the increasing column density with decreasing impact parameter relationship found for the smaller mass galaxy halos. In addition, while the covering fraction within R vir is lower for clusters than galaxies, beyond R vir the covering fraction is somewhat higher for clusters. The velocity dispersion of the absorbers compared to the galaxies is higher for Coma, consistent with the absorbers tracing additional turbulent gas motions in the cluster outskirts. The results are overall consistent with cosmological simulations, with the covering fraction being high in the observations standing out as the primary discrepancy.

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Weighing Galaxy Clusters With Gas. Ii. On the Origin of Hydrostatic Mass Bias in Λcdm Galaxy Clusters

Cited by 153 publications

References 34 publications

Testing for X-Ray–SZ Differences and Redshift Evolution in the X-Ray Morphology of Galaxy Clusters

Testing for X-Ray–SZ Differences and Redshift Evolution in the X-Ray Morphology of Galaxy Clusters

Rhapsody-G simulations I: the cool cores, hot gas and stellar content of massive galaxy clusters

Lyα Absorbers and the Coma Cluster

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