Improved forecasts for the baryon acoustic oscillations and cosmological distance scale

We present the cosmological distance errors achievable using the baryonic acoustic oscillations as a standard ruler. We begin from a Fisher matrix formalism that is upgraded from earlier Seo and Eisenstein work. We isolate the information from the baryonic peaks by excluding distance information from other less robust sources. Meanwhile, we accommodate the Lagrangian displacement distribution into the Fisher matrix calculation to reflect the gradual loss of information in scale and in time due to nonlinear growth, nonlinear bias, and nonlinear redshift distortions. We then show that we can contract the multidimensional Fisher matrix calculations into a two-dimensional or even one-dimensional formalism with physically motivated approximations. We present the resulting fitting formula for the cosmological distance errors from galaxy redshift surveys as a function of survey parameters and nonlinearity, which saves us going through the 12 dimensional Fisher matrix calculations. Finally, we show excellent agreement between the distance error estimates from the revised Fisher matrix and the precision on the distance scale recovered from N-body simulations.