Measuring cosmological parameters with galaxy surveys

Abstract

We assess the accuracy with which future galaxy surveys can measure cosmological parameters by deriving a handy approximation that we validate numerically. We find that galaxy surveys are quite complementary to future Cosmic Microwave Background (CMB) experiments. By breaking parameter degeneracies of the Planck CMB satellite in a cold dark matter cosmology, the Sloan Digital Sky Survey might be able to reduce the Planck error bars by about an order of magnitude on the large-scale power normalization and the reionization optical depth, down to percent levels. However, pinpointing attainable accuracies to within better than a factor of a few depends crucially on whether it will be possible to extract useful information from the mildly nonlinear regime.

Minor changes in published version. 6 pages with 2 figs included. Color figure and links at http://www.sns.ias.edu/~max/galfisher.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/galfisher.html (faster from Europe) or from max@ias.edu