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Lubini

Fakultäten » Mathematisch-naturwissenschaftliche Fakultät » Physik-Institut » Prof. Dr. Philippe Jetzer » Lubini

Completed research project

Title / Titel Multi-wavelength strong lensing analysis of baryons and dark matter
in dynamically active clusters
PDF Abstract (PDF, 14 KB)
Summary / Zusammenfassung Knowledge of the intrinsic shape of galaxy clusters is very important in investigating
cosmic structure formation and astrophysical processes. In fact, the intrinsic structure
directly suggests how material aggregates from large-scale perturbations and also contains
evidence about the nature and mechanisms of interaction of baryons and DM, since
processes such as virialization, dissipation or gas cooling tend to make systems more
spherical, especially in the inner regions. In this framework we completed our strong
lensing analysis of the galaxy cluster AC 114. With respect to our first proposal of a
multi-wavelength lensing method exploiting both optical and X-ray observations, we employed
a more powerful Bayesian approach for model comparison. The DM distribution
in the cluster turned out to be in remarkable agreement with predictions from N-body
simulations.
Precision cosmology era requires independent methods to probe the matter/energy content
of the Universe. We are developing a statistical strong lensing approach to probe
the cosmological parameters exploiting multiple redshift image systems behind massive
galaxy clusters. Our method relies on non-parametric mass inversion of galaxy clusters,
which provides an unbiased estimate of the cosmological parameters. We consider the
statistical dispersion of the parameter space describing the mass distribution to obtain
information about the assumed cosmological model. By sampling the cosmological parameter
space and employing a Bayesian approach for model comparison, we will be able
to infer the probability distributions of the cosmological parameters. We have developed
a new algorithm based on a random walk, that gives an unbiased and random sample of
the solution set in parameter space. This is needed for our statistical analysis, since we
are dealing with high dimensional parameter spaces, where the former algorithm is inapt
for the above-mentioned purposes. We have now defined the theoretical framework of the
statistical tools, implemented the algorithm in the software for the mass inversion and
are now testing the developed algorithm.
Publications / Publikationen Astron. and Astrophys., Volume 518, (2010), pp. A55
Project leadership and contacts /
Projektleitung und Kontakte
Mario Lubini (Project Leader) lubini@physik.uzh.ch
Prof. Philippe Jetzer jetzer@physik.uzh.ch
Funding source(s) /
Unterstützt durch
SNF (Personen- und Projektförderung)
 
In collaboration with /
In Zusammenarbeit mit
Dr. Mauro Sereno, Politecnico Torino Italy
Duration of Project / Projektdauer Jul 2010 to Sep 2012