PubMed Health⌕ Search

Biomedical subjects

R Durrer

Publications and source records attributed to R Durrer.

9 recordsLinked to original sources

Cosmic microwave background anisotropies with mixed isocurvature perturbations.

In the light of the recent high quality data of the cosmic microwave background anisotropies, several estimations of cosmological parameters have been published. We study to what extent these estimations depend on assumptions about the initial conditions of the cosmological perturbations, which are usually supposed to be adiabatic. We show that, for more generic initial conditions, not only the best fit values are very different but the allowed parameter range enlarges dramatically. This raises the question which cosmological information (matter content of the Universe vs physics of inflation) can be reliably extracted from these data.

Journal Article↗

Biasing in Gaussian Random Fields and Galaxy Correlations.

In this Letter, we show that in a Gaussian random field, the correlation length-the typical size of correlated structures-does not change with biasing. We interpret the amplification of the correlation functions of subsets identified by different thresholds as being caused by the increasing sparseness of peaks over threshold. This clarifies a long-standing misconception in the literature. We also argue that this effect does not explain the observed increase of the amplitude of the correlation function xi(r) when galaxies of brighter luminosity or galaxy clusters of increasing richness are considered.

Journal Article↗