Fakultäten » Mathematischnaturwissenschaftliche Fakultät » PhysikInstitut » Prof. Dr. Philippe Jetzer » Lubini
Title / Titel  Multiwavelength strong lensing analysis of baryons and dark matter in dynamically active clusters 


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 largescale 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 multiwavelength lensing method exploiting both optical and Xray 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 Nbody 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 nonparametric 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 abovementioned 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 


Funding source(s) / Unterstützt durch 
SNF (Personen und Projektförderung) 

In collaboration with / In Zusammenarbeit mit 


Duration of Project / Projektdauer  Jul 2010 to Sep 2012 