Cluster mass profiles from X‐ray observations: Present constraints and limitations

Ettori, S.

doi:10.1002/asna.201211856

Cited by 3 publications

(2 citation statements)

References 49 publications

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“…Self-similar modelling includes evolution of the scaling relation normalisations with the Hubble expansion, which is routinely measured (e.g. Reichert et al 2011;Ettori 2013). Evolution effects beyond self-similarity, e.g.…”

Section: Introductionmentioning

confidence: 99%

The 400d Galaxy Cluster Survey weak lensing programme: III: Evidence for consistent WL and X-ray masses at $z\approx 0.5$

Israel,

Reiprich,

Erben

et al. 2014

Preprint

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Context. Scaling properties of galaxy cluster observables with cluster mass provide central insights into the processes shaping clusters. Calibrating proxies for cluster mass that are relatively cheap to observe will moreover be crucial to harvest the cosmological information available from the number and growth of clusters with upcoming surveys like eROSITA and Euclid. The recent Planck results led to suggestions that X-ray masses might be biased low by ∼ 40 %, more than previously considered. Aims. We aim to extend knowledge of the weak lensing -X-ray mass scaling towards lower masses (as low as 1×10 14 M ) in a sample representative of the z ∼ 0.4-0.5 population. Thus, we extend the direct calibration of cluster mass estimates to higher redshifts. Methods. We investigate the scaling behaviour of MMT/Megacam weak lensing (WL) masses for 8 clusters at 0.39 ≤ z ≤ 0.80 as part of the 400d WL programme with hydrostatic Chandra X-ray masses as well as those based on the proxies, e.g. Y X = T X M gas .Results. Overall, we find good agreement between WL and X-ray masses, with different mass bias estimators all consistent with zero. When subdividing the sample into a low-mass and a high-mass subsample, we find the high-mass subsample to show no significant mass bias while for the low-mass subsample, there is a bias towards overestimated X-ray masses at the ∼ 2σ level for some mass proxies. The overall scatter in the mass-mass scaling relations is surprisingly low. Investigating possible causes, we find that neither the greater range in WL than in X-ray masses nor the small scatter can be traced back to the parameter settings in the WL analysis. Conclusions. We do not find evidence for a strong (∼ 40 %) underestimate in the X-ray masses, as suggested to reconcile recent Planck cluster counts and cosmological constraints. For high-mass clusters, our measurements are consistent with other studies in the literature. The mass dependent bias, significant at ∼ 2σ, may hint at a physically different cluster population (less relaxed clusters with more substructure and mergers); or it may be due to small number statistics. Further studies of low-mass high-z lensing clusters will elucidate their mass scaling behaviour.

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Section: Introductionmentioning

confidence: 99%

The 400d Galaxy Cluster Survey weak lensing programme: III: Evidence for consistent WL and X-ray masses at $z\approx 0.5$

Israel,

Reiprich,

Erben

et al. 2014

Preprint

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“…The progress in deriving galaxy cluster masses and mass profiles from X-ray observations was part of the discussion of the conference. An overview on this topic can be found in Ettori (2013) and further contributions by Wilson et al (2013) and Lyskova (2013). Wile about 15-20 years ago discrepancies in mass measurements with different methods of more than a factor of two have been hotly debated, recent comparison of lensing and X-ray measurements of cluster masses shown at the meeting has now converged to mean uncertainties of the mass calibration of 10-20 %.…”

Section: Cluster Massesmentioning

confidence: 99%

X‐ray galaxy cluster studies for astro‐physics and cosmology

Böhringer

Schartel

2013

Astron Nachr

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The field of research on galaxy clusters has received an enormous increase in attention in the last years, since galaxy clusters have been more and more recognized as very important laboratories for astrophysical studies and observational probes for testing cosmological models. X-ray observations of these largest clearly defined objects in our Universe have been by far the most fruitful approach that has provided us with rich astrophysical and cosmological insights. ESA's XMM-Newton and NASA's Chandra observatories have been the powerhorses of this research. In this article we therefore like to summarize the major advances made in the field of galaxy cluster research primarily by these two instruments. We will touch the progress in understanding the structure of galaxy clusters and its statistics, the AGN feedback processes in the center of clusters, cosmic evolution of clusters, cluster mass measurements, the thermodynamic structure of the intracluster medium and its chemistry, X-ray surveys of clusters, and the use of galaxy clusters for cosmological tests.

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The 400d Galaxy Cluster Survey weak lensing programme

Israel

Reiprich²,

Erben³

et al. 2014

A&A

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Context. Scaling properties of galaxy cluster observables with cluster mass provide central insights into the processes shaping clusters. Calibrating proxies for cluster mass that are relatively cheap to observe will moreover be crucial to harvest the cosmological information available from the number and growth of clusters with upcoming surveys like eROSITA and Euclid. The recent Planck results led to suggestions that X-ray masses might be biased low by ∼40%, more than previously considered. Aims. We aim to extend knowledge of the weak lensing -X-ray mass scaling towards lower masses (as low as 1 × 10 14 M ) in a sample representative of the z ∼ 0.4-0.5 population. Thus, we extend the direct calibration of cluster mass estimates to higher redshifts. Methods. We investigate the scaling behaviour of MMT/Megacam weak lensing (WL) masses for 8 clusters at 0.39 ≤ z ≤ 0.80 as part of the 400d WL programme with hydrostatic Chandra X-ray masses as well as those based on the proxies, e.g. Y X = T X M gas . Results. Overall, we find good agreement between WL and X-ray masses, with different mass bias estimators all consistent with zero. When subdividing the sample into a low-mass and a high-mass subsample, we find the high-mass subsample to show no significant mass bias while for the low-mass subsample, there is a bias towards overestimated X-ray masses at the ∼2σ level for some mass proxies. The overall scatter in the mass-mass scaling relations is surprisingly low. Investigating possible causes, we find that neither the greater range in WL than in X-ray masses nor the small scatter can be traced back to the parameter settings in the WL analysis. Conclusions. We do not find evidence for a strong (∼40%) underestimate in the X-ray masses, as suggested to reconcile recent Planck cluster counts and cosmological constraints. For high-mass clusters, our measurements are consistent with other studies in the literature. The mass dependent bias, significant at ∼2σ, may hint at a physically different cluster population (less relaxed clusters with more substructure and mergers); or it may be due to small number statistics. Further studies of low-mass high-z lensing clusters will elucidate their mass scaling behaviour.

show abstract

Cluster mass profiles from X‐ray observations: Present constraints and limitations

Cited by 3 publications

References 49 publications

The 400d Galaxy Cluster Survey weak lensing programme: III: Evidence for consistent WL and X-ray masses at $z\approx 0.5$

The 400d Galaxy Cluster Survey weak lensing programme: III: Evidence for consistent WL and X-ray masses at $z\approx 0.5$

X‐ray galaxy cluster studies for astro‐physics and cosmology

The 400d Galaxy Cluster Survey weak lensing programme

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