Disentangling redshift-space distortions and non-linear bias using the 2D power spectrum

We present the 2D redshift-space galaxy power spectrum, P(k, mu), measured from the Dark Sky simulations, using catalogues constructed with halo occupation distribution and subhalo abundance matching methods, chosen to represent an intermediate redshift sample of luminous red galaxies. We find that the information content in individual mu (cosine of the angle to the line of sight) bins is substantially richer then multipole moments, and show that this can be used to isolate the impact of non-linear growth and redshift-space distortion (RSD) effects. Using the mu < 0.2 simulation data, which is not impacted by RSD, we can successfully measure the non-linear bias to similar to 5 per cent at k < 0.6 h Mpc(-1). Using the low mu simulation data to constrain the non-linear bias, and mu >= 0.2 to constrain the growth rate, we show that f can be constrained to similar to 26(22) per cent to a k(max) < 0.4(0.6) h Mpc(-1) from clustering alone using a dispersion model, for a range of galaxy models. Our analysis of individual mu bins reveals interesting physical effects which arise from different methods of populating haloes with galaxies. We find a prominent turnaround scale, at which RSD damping effects are greater than the nonlinear growth, which differs for each galaxy model. The idea of separating non-linear growth and RSD effects making use of the full information in the 2D galaxy power spectrum yields significant improvements in constraining cosmological parameters and may be a promising probe of galaxy formation models.