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