Towards more realistic forecasting of dark energy constraints from galaxy redshift surveys

Galaxy redshift surveys are becoming increasingly important as a dark energy probe. We improve the forecasting of dark energy constraints from galaxy redshift surveys by using the 'dewiggled' galaxy power spectrum, P-dw(k), in the Fisher matrix calculations. Since P-dw(k) is a good fit to real galaxy clustering data over most of the scale range of interest, our approach is more realistic compared to previous work in forecasting dark energy constraints from galaxy redshift surveys. We find that our new approach gives results in excellent agreement when compared to the results from the actual data analysis of the clustering of the Sloan Digital Sky Survey Data Release 7 luminous red galaxies. We provide forecasts of the dark energy constraints from a plausible Stage IV galaxy redshift survey.