Statistical and systematic errors in redshift-space distortion
  measurements from large surveys
  We investigate the impact of statistical and systematic errors on
measurements of linear redshift-space distortions (RSD) in future cosmological
surveys, analyzing large catalogues of dark-matter halos from the BASICC
simulation. These allow us to estimate the dependence of errors on typical
survey properties, as volume, galaxy density and mass (i.e. bias factor) of the
adopted tracer. We find that measures of the specific growth rate \beta=f/b
using the Hamilton/Kaiser harmonic expansion of the redshift-space correlation
function \xi(r_p,\pi) on scales larger than 3/h Mpc are typically
under-estimated by up to 10% for galaxy sized halos. This is significantly
larger than the corresponding statistical errors, which amount to a few
percent, indicating the importance of non-linear improvements to the Kaiser
model to obtain accurate measurements of the growth rate. We compare the
statistical errors to predictions obtained with the Fisher information matrix,
based on the usual FKP prescription for the errors on the power spectrum. We
show that this produces parameter errors fairly similar to the standard
deviations from the halo catalogues, but only if applied to strictly linear
scales in Fourier space (k<0.2 h/Mpc). Finally, we present an accurate scaling
formula describing the relative error on {\beta} as a function of the survey
parameters, which closely matches the simulation results in all explored
regimes. This provides a handy and plausibly more realistic alternative to the
Fisher matrix approach, to quickly and accurately predict RSD statistical
errors expected from future surveys.
