Author : Irène Balmès
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (892 download)
Book Synopsis Alternative Probes in Cosmology by : Irène Balmès
Download or read book Alternative Probes in Cosmology written by Irène Balmès and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this thesis was to study cosmological probes. We focused on time-delays in lenses and density profiles of halos. For the former, we use Bayesian methods to test strong lens models and select a subsample suitable for cosmological parameter inference. To this end we apply a Bayes factor analysis to synthetic catalogs of lense. with angular structure. We focus on double lenses. Through a likelihood analysis we recover the input value of HO to within 3sigma statistical uncertainty. We apply this methodology to observed double lenses and obtain three lenses in which a simple power-law model is favored. Assuming a flat ACDM cosmology, the combined likelihood data analysis of such systems gives h = 0.76+0.15-0.05. The next generation of cosmic structure surveys will provide larger lens datasets and this method can be useful to select homogeneous lens subsamples adapted to unbiased cosmological parameter inference. In a second part we focus on the imprint of dark energy on the density profile of Dark Matter halos using cosmological N-body simulations from DEUSS. We first focus on the analysis of the chi-square of the NFW profile. The fraction of halos ill-fitted varies with cosmology, indicating that the mass assembly in unrelaxed halos carries a signature of dark energy. To access this information independently of the NFW profile, we introduce a new observable quantity: the sparsity. This is defined as the ratio of masses M200/MDelta. We find the average sparsity to be nearly independent of the total halo mass. Most importantly, we find that the sparsity varies significantly with the underlying dark energy model, thus providing an alternative cosmological test.