Probing the Dark Matter and Gas Fraction in Relaxed Galaxy Groups with X‐Ray Observations from<i>Chandra</i>and<i>XMM‐Newton</i>

Gastaldello, F.; Buote, David A.; Humphrey, Philip J.; Zappacosta, L.; Bullock, James S.; Brighenti, Fabrizio; Mathews, William G.

doi:10.1086/521519

Cited by 164 publications

(297 citation statements)

References 114 publications

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“…Fortunately there is some overlap between our groups and those of Sun et al (2009) and also Gastaldello et al (2007 , we found that on average our temperatures are in agreement (10 log T −log T Sun = 1.09 +0.13 −0.12 ). Differences in the individual cluster temperatures may be caused by the different temperature determinations applied.…”

Section: Discussionmentioning

confidence: 52%

Testing the low-mass end of X-ray scaling relations with a sample ofChandragalaxy groups

Eckmiller

Hudson

Reiprich

2011

A&A

127

183

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Context. Well-determined scaling relations between X-ray observables and cluster mass are essential for using large cluster samples to constrain fundamental cosmological parameters. Scaling relations between cluster masses and observables, such as the luminositytemperature, mass-temperature, luminosity-mass relations, have been investigated extensively, however the question of whether these relations hold true also for poor clusters and groups remains unsettled. Some evidence supports a "break" at the low end of the group/cluster mass range, possibly caused by the stronger influence of non-gravitational physics on low-mass systems. Aims. The main goal of this work is to test local scaling relations for the low-mass range in order to check whether or not there is a systematic difference between clusters and groups, and to thereby extend this method of reliable and convenient cluster mass determination for future large samples down to the group regime. Methods. We compiled a statistically complete sample of 112 X-ray galaxy groups, 26 of which have usable Chandra data. Temperature, metallicity, and surface brightness profiles were created for these 26 groups, and used to determine the main physical quantities and scaling relations. We then compared the group properties to those of the HIFLUGCS clusters, as well as several other group and cluster samples. Results. We present radial profiles for the individual objects and scaling relations of the whole sample (. Temperature and metallicity profiles behave universally, except for the core regions.and L x − Y x relations of the group sample are generally in good agreement with clusters. The L x − T relation steepens for T < 3 keV, which could point to a larger impact of heating mechanisms on cooler systems. We found a significant drop in the gas mass fraction below < ∼ 1 keV, as well as a correlation with radius, which indicates the ICM is less dominant in groups compared to clusters and the galaxies have a stronger influence on the global properties of the system. In all relations the intrinsic scatter for groups is larger than for clusters, which appears not to be correlated with merger activity but could be due to scatter caused by baryonic physics in the group cores. We also demonstrate the importance of selection effects. Conclusions. We have found some evidence for a similarity break between groups and clusters. However this does not have a strong effect on the scaling relations.

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Section: Discussionmentioning

confidence: 52%

Testing the low-mass end of X-ray scaling relations with a sample ofChandragalaxy groups

Eckmiller

Hudson

Reiprich

2011

A&A

127

183

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“…This model has been shown to be an adequate fit to the mass profiles of many morphologically relaxed systems (e.g., Pratt & Arnaud 2002;Pointecouteau et al 2005;Vikhlinin et al 2006;Gastaldello et al 2007). We emphasise that for the present investigation we use it only as a convenient fitting formula that allows direct comparison with the equivalent weak lensing parameterisations.…”

Section: Concentrationmentioning

confidence: 99%

Planckintermediate results

Ade¹,

Aghanim²,

Arnaud³

et al. 2013

A&A

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We examine the relation between the galaxy cluster mass M and Sunyaev-Zeldovich (SZ) effect signal D 2 A Y 500 for a sample of 19 objects for which weak lensing (WL) mass measurements obtained from Subaru Telescope data are available in the literature. Hydrostatic X-ray masses are derived from XMM-Newton archive data, and the SZ effect signal is measured from Planck all-sky survey data. We find an M WL −D 2 A Y 500 relation that is consistent in slope and normalisation with previous determinations using weak lensing masses; however, there is a normalisation offset with respect to previous measures based on hydrostatic X-ray mass-proxy relations. We verify that our SZ effect measurements are in excellent agreement with previous determinations from Planck data. For the present sample, the hydrostatic X-ray masses at R 500 are on average ∼20 percent larger than the corresponding weak lensing masses, which is contrary to expectations. We show that the mass discrepancy is driven by a difference in mass concentration as measured by the two methods and, for the present sample, that the mass discrepancy and difference in mass concentration are especially large for disturbed systems. The mass discrepancy is also linked to the offset in centres used by the X-ray and weak lensing analyses, which again is most important in disturbed systems. We outline several approaches that are needed to help achieve convergence in cluster mass measurement with X-ray and weak lensing observations.

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“…The knowledge of these components has been growing thanks to the many efforts involved in collecting suitable blank sky fields to be used as template background by the XMM-Newton users [4,5], the analysis of the XMM-Newton Guest Observer Facility leading to the XMMNewton Extended Source Analysis Software [6,7], the efforts of the XMMNewton SOC 1 and the contributions of various research teams, among them our in Milan has been particularly active on this topic [8,9,10]. A summary table of the EPIC instrumental background components is available at this link 2 .…”

Section: The Current Knowledge Of the Xmm-newton Backgroundmentioning

confidence: 99%