Related papers: The cluster abundance in cosmic string models for …
We discuss structure formation in cosmic string theories. Emphasis is laid on the properties of the peculiar velocity field, non-gaussian features and clusters of galaxies. It is found that the predicted peculiar velocity field is quiet…
We present the first cosmological constraints from a joint analysis of galaxy clustering and galaxy-galaxy lensing using extended SubHalo Abundance Matching (SHAMe). We analyse stellar mass-selected Galaxy And Mass Assembly (GAMA) galaxy…
In gaussian theories of structure formation, the galaxy cluster abundance is an extremely sensitive probe of the density fluctuation power spectrum and of the density parameter, $\Omega$. We develop this theme by deriving and studying in…
In cosmological models where local cosmic strings are formed at the end of a period of inflation, the perturbations are seeded both by the defects and by the quantum fluctuations. In a subset of these models, for example those based on…
We use the galaxy cluster X-ray temperature distribution function to constrain the amplitude of the power spectrum of density inhomogeneities on the scale corresponding to clusters. We carry out the analysis for critical density universes,…
We use the X-ray power spectrum of the ROSAT all-sky survey in the R6 band (approximately 0.9-1.3 keV) to set an upper limit on the galaxy cluster power spectrum. The cluster power spectrum is modelled with a minimum number of robust…
We find that the observed log N - log S relation of X-ray clusters can be reproduced remarkably well with a certain range of values for the fluctuation amplitude $\sigma_8$ and the cosmological density parameter $\Omega_0$ in cold dark…
We determine the linear amplitude of mass fluctuations in the universe, sigma_8, from the abundance of massive clusters at redshifts z=0.5 to 0.8. The evolution of massive clusters depends exponentially on the amplitude of mass fluctuations…
We examine the effects of cosmic strings on structure formation and on the ionization history of the universe. While Gaussian perturbations from inflation are known to provide the dominant contribution to the large scale structure of the…
Scaling relations of observed galaxy cluster properties are useful tools for constraining cosmological parameters as well as cluster formation histories. One of the key cosmological parameters, sigma8, is constrained using observed clusters…
The joint analysis of clustering and stacked gravitational lensing of galaxy clusters in large surveys can constrain the formation and evolution of structures and the cosmological parameters. On scales outside a few virial radii, the halo…
We put robust upper limits on the average cosmological density \Omega_s of cosmic strings based on the variability properties of a large homogeneous sample of SDSS quasars. We search for an excess of characteristic variations of quasar…
We present optimal Bayesian field-level cosmological constraints from nonlinear tracers of the large-scale structure, specifically the amplitude $\sigma_8$ of linear matter fluctuations inferred from rest-frame simulated dark matter halos…
The amplitude of cosmological density fluctuations, sigma_8, has been studied and estimated by analysing many cosmological observations. The values of the estimates vary considerably between the various probes. However, different estimators…
I report on recent numerical simulations of the simplest field theory with cosmic string solutions, the Abelian Higgs model. We find that random networks of string quickly converge to a scaling solution in which the network scale length…
We present the clustering of galaxy clusters as a useful addition to the common set of cosmological observables. The clustering of clusters probes the large-scale structure of the Universe, extending galaxy clustering analysis to the…
We use semi-analytic modelling of the galaxy-cluster population and its strong lensing efficiency to explore how the expected abundance of large gravitational arcs on the sky depends on $\sigma_8$. Our models take all effects into account…
The COBE detection of microwave anisotropies provides the best way of fixing the amplitude of cosmological fluctuations on the largest scales. We discuss the impact of this new, precise normalization and give fitting formulae for the…
We compare various physically different measurements of linear matter density perturbation amplitude, $sigma_8$, which are obtained from the observations of CMB anisotropy, galaxy cluster mass function, weak gravitation lensing, matter…
Cosmic superstrings of string theory differ from conventional cosmic strings of field theory. We review how the physical and cosmological properties of the macroscopic string loops influence experimental searches for these relics from the…