Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2011-04-07
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
27 pages, 15 figures; extended and improved modelling, main conclusions unchanged, otherwise minor changes to match accepted v
Scientific paper
We investigate the information on cosmology contained in Gaussianised weak gravitational lensing convergence fields. Employing Box-Cox transformations to determine optimal transformations to Gaussianity, we develop analytical models for the transformed power spectrum, including effects of noise and smoothing. We find that optimised Box-Cox transformations perform substantially better than an offset logarithmic transformation in Gaussianising the convergence, but both yield very similar results for the signal-to-noise and parameter constraints. None of the transformations is capable of eliminating correlations of the power spectra between different angular frequencies, which we demonstrate to have a significant impact on the errors on cosmology. Analytic models of the Gaussianised power spectrum yield good fits to the simulations and produce unbiased parameter estimates in the majority of cases, where the exceptions can be traced back to the limitations in modelling the higher-order correlations of the original convergence. In the idealistic case, without galaxy shape noise, we find an increase in cumulative signal-to-noise by a factor of 2.6 for angular frequencies up to 1500, and a decrease in the area of the confidence region in the Omega_m-sigma_8 plane by a factor of 4.4 in terms of q-values for the best-performing transformation. When adding a realistic level of shape noise, all transformations perform poorly with little decorrelation of angular frequencies, a maximum increase in signal-to-noise of 34%, and even marginally degraded errors on cosmological parameters. We argue that, to find Gaussianising transformations of practical use, one will need to go beyond transformations of the one-point distribution of the convergence, extend the analysis deeper into the non-linear regime, and resort to an exploration of parameter space via simulations. (abridged)
Joachimi Benjamin
Kiessling Andreas
Taylor Andy N.
No associations
LandOfFree
Cosmological information in Gaussianised weak lensing signals does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Cosmological information in Gaussianised weak lensing signals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cosmological information in Gaussianised weak lensing signals will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-718144