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Cosmological and large-scale structure studies with X-ray galaxy clusters
Hans Böhringer (LMU)
Thursday 16/01/2020 @ 11:30, Sala IV piano Battiferro
Based on our X-ray selected sample of galaxy clusters, REFLEX and NORAS, we study the statistics of galaxy cluster properties, the cluster clustering, and superclusters. We use the X-ray luminosity function of galaxy clusters to constrain cosmological parameters, in particular the matter density and the large-scale structure fluctuation amplitude. While we find in general good agreement with predictions of the concordance Lambda-CMD model, we observe a discrepancy in the above mentioned parameters compared to the results of the Planck Survey. This could be the results of unaccounted systematics, but it could also be the effect of massive neutrinos on the evolution of the large-scale structure. We also use the cluster population to chart the matter density in the nearby Universe. We find that the local environment out to a radius of about 90 - 170 Mpc has a lower than mean density. This has the effect that a locally measured Hubble parameter is larger than the cosmic mean.