The detectability of baryonic acoustic oscillations in future galaxy surveys

We use N-body simulations of the hierarchical clustering of dark matter and semi-analytical modelling of galaxy formation to assess the detectability of baryonic acoustic oscillations in the power spectrum of galaxies. Our primary simulation has a volume of $2.4 h^{-3} {\rm Gpc}^{3}$, comparable to forthcoming redshift surveys at $z \sim 1$, with sufficient mass resolution to see the galaxies expected in these surveys. We present a step-by-step illustration of the effects which change the form of the galaxy power spectrum on large scales from the simple predictions of linear theory. Nonlinear effects are evident on scales in excess of $100 h^{-1}$Mpc. Nonlinearities, galaxy bias and redshift-space distortions erase some of the acoustic oscillations. We present an improved, robust method to find the equation of state of the dark energy parameter $w$. Our galaxy formation model allows us to construct synthetic galaxy samples with the selection criteria proposed for future surveys. We find a weak systematic difference between the equation of state parameter recovered using galaxies and dark matter. Sampling variance is the dominant source of error despite the huge volume simulated. We use our simulation results to estimate the accuracy with which $w$ will be measured in the future. Pan-STARRS could potentially yield a measurement with an accuracy of $\Delta w = 4-7%$, which is competitive with the proposed WFMOS survey ($\Delta w = 5%$). This represents a factor of two improvement over current constraints on $w$. To achieve $\Delta w \sim 1%$ using acoustic oscillations would require a survey with at least 16 times the effective volume of Pan-STARRS. Thus, it is unlikely that this level of accuracy will be reached by the next generation of galaxy surveys.