Developing galaxy-cluster potentials into a cosmological diagnostic
Final Report Abstract
Based on earlier work, we could show in this project that: • Three-dimensional gravitational potentials can be reconstructed by applying the Richardson-Lucy deprojection technique on X-ray, thermal Sunyaev-Zel’dovich, and gravitational lensing data. In these reconstructions, deprojection kernels with different symmetries (spherical, spheroidal, triaxial) can be used. • Gravitational potentials obtained from all available types of cluster data can be combined, weighing them inversely proportionally to their intrinsic scatter. Such combinations increase the accuracy of the potential reconstructions substantially. • In this procedure, free-form reconstruction algorithms such as SaWLens, originally developed for unbiased reconstructions of gravitational lensing, can be extended to other types of data. • As anticipated, the gravitational potential is much less sensitive to deviations from idealised symmetries and to substructures that reconstructions of the matter or gas density. This also implies that cluster cosmology based on gravitational potentials can be extended to samples of dynamically active, unrelaxed galaxy clusters, which need to be excluded from mass- or density-based studies. • By recovering unique gravitational potentials from joint analyses of all available data, the accuracy of physical cluster characterisations can be substantially increased, and the scatter substantially lowered. We thus conclude that the goal of this project could be achieved. If cluster potentials can be recovered in large numbers, their statistical interpretation in terms of cosmological models is possible via the cluster potential function (a replacement of the conventional mass function) which we have derived in earlier work.
Publications
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Reconstruction of the two-dimensional gravitational potential of galaxy clusters from X-ray and Sunyaev-Zel’dovich measurements. Astronomy & Astrophysics, 614, A38.
Tchernin, C.; Bartelmann, M.; Huber, K.; Dekel, A.; Hurier, G.; Majer, C. L.; Meyer, S.; Zinger, E.; Eckert, D.; Meneghetti, M. & Merten, J.
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Joint cluster reconstructions. Astronomy & Astrophysics, 627, A143.
Huber, Korbinian; Tchernin, Céline; Merten, Julian; Hilbert, Stefan & Bartelmann, Matthias
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Characterizing galaxy clusters by their gravitational potential: Systematics of cluster potential reconstruction. Astronomy & Astrophysics, 644, A126.
Tchernin, C.; Lau, E. T.; Stapelberg, S.; Hug, D. & Bartelmann, M.
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Triaxiality in galaxy clusters: Mass versus potential reconstructions. Astronomy & Astrophysics, 663, A17.
Stapelberg, S.; Tchernin, C.; Hug, D.; Lau, E. T. & Bartelmann, M.
