HICOSMO - Cosmology with a complete sample of galaxy clusters: I. Data analysis, sample selection and luminosity-mass scaling-relation

Abstract

The X-ray regime, where the most massive visible component of galaxy clusters, the intra cluster medium (ICM), is visible, offers directly measured quantities, like the luminosity, and derived quantities, like the total mass, to characterize these objects. The aim of this project is to analyze a complete sample of galaxy clusters in detail and constrain cosmological parameters, like the matter density, OmegaM, or the amplitude of initial density fluctuations, sigma8. The purely X-ray flux-limited sample (HIFLUGCS) consists of the 64 X-ray brightest galaxy clusters, which are excellent targets to study the systematic effects, that can bias results. We analyzed in total 196 Chandra observations of the 64 HIFLUGCS clusters, with a total exposure time of 7.7 Ms. Here we present our data analysis procedure (including an automated substructure detection and an energy band optimization for surface brightness profile analysis) which gives individually determined, robust total mass estimates. These masses are tested against dynamical and Planck Sunyaev-Zeldovich (SZ) derived masses of the same clusters, where good overall agreement is found with the dynamical masses. The Planck SZ masses seem to show a mass dependent bias to our hydrostatic masses; possible biases in this mass-mass comparison are discussed including the Planck selection function. Furthermore, we show the results for the 0.1-2.4-keV-luminosity vs. mass scaling-relation. The overall slope of the sample (1.34) is in agreement with expectations and values from literature. Splitting the sample into galaxy groups and clusters reveals, even after a selection bias correction, that galaxy groups exhibit a significantly steeper slope (1.88) compared to clusters (1.06).

21 pages + 29 pages appendix (figures and tables), accepted by MNRAS, small corrections incorporated

References in corpus (12)

• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• The Canadian Cluster Comparison Project: detailed study of systematics and updated weak lensing masses
• Statistics of X-ray observables for the cooling-core and non-cooling core galaxy clusters
• Scaling Properties of a Complete X-ray Selected Galaxy Group Sample
• Cosmology and Astrophysics from Relaxed Galaxy Clusters II: Cosmological Constraints
• On the efficiency and reliability of cluster mass estimates based on member galaxies
• LoCuSS: Comparison of Observed X-ray and Lensing Galaxy Cluster Scaling Relations with Simulations
• XMM-Newton and Chandra Cross Calibration Using HIFLUGCS Galaxy Clusters: Systematic Temperature Differences and Cosmological Impact
• Probing the Dark Matter and Gas Fraction in Relaxed Galaxy Groups with X-ray observations from Chandra and XMM
• Direct X-ray Spectral Deprojection of Galaxy Clusters
• CoMaLit - II. The scaling relation between mass and Sunyaev-Zel'dovich signal for Planck selected galaxy clusters
• Extending the $L_{\mathrm{X}}-T$ relation from clusters to groups-Impact of cool core nature, AGN feedback, and selection effects

Cited by in corpus (6)

• The galaxy cluster mass scale and its impact on cosmological constraints from the cluster population
• HICOSMO - Cosmology with a complete sample of galaxy clusters: II. Cosmological results
• NGC 741 - Mergers and AGN feedback on galaxy group scale
• Building a cluster: shocks, cavities, and cooling filaments in the group-group merger NGC 6338
• Projection effects in galaxy cluster samples: insights from X-ray redshifts
• Average Dark Matter Halo Sparsity Relations as Consistency Check of Mass Estimates in Galaxy Cluster Samples