Scale dependence of the bias investigated by weak lensing
Abstract
Description
The statistical analysis of the lensing effects coupled with the statistical analysis of the number counts is a tool to probe directly the relation between the mass and the light. In particular, some properties of the bias parameter can be investigated. The correlation between the shear of a given population of galaxies, and the number counts of a different population of galaxies along the same line of sight is calculated for the linear and the non-linear power spectra of density fluctuations for different cosmologies. The estimator R defined as the ratio of this correlation and the variance of the number counts is inversely proportional to the bias parameter. Unfortunately, R is highly dependent on the cosmological model, which makes a direct measure of the bias quite difficult. However, it is showed that Rb is independent on the power spectrum and the smoothing scale, thus R is a direct measure of the inverse of the bias times a function of the cosmological parameters. From R, a new estimator is defined which is only sensible to the scale dependence of the bias. It is showed that with a sample of 25 square degrees, one can measure a scale variation of the bias larger than 20% in the 1' to 10' scale range, almost independently of the cosmological parameters, the redshift distribution of the galaxies, and the power spectrum.
13 pages, LateX, 13 figures included, submitted to A&A
13 pages, LateX, 13 figures included, submitted to A&A