Information content in the redshift-space galaxy power spectrum and
  bispectrum
  We present a Fisher information study of the statistical impact of galaxy
bias and selection effects on the estimation of key cosmological parameters
from galaxy redshift surveys; in particular, the angular diameter distance,
Hubble parameter, and linear growth rate at a given redshift, the cold dark
matter density, and the tilt and running of the primordial power spectrum. The
line-of-sight-dependent selection contributions we include here are known to
exist in real galaxy samples. We determine the maximum wavenumber included in
the analysis by requiring that the next-order corrections to the galaxy power
spectrum or bispectrum, treated here at next-to-leading and leading order,
respectively, produce shifts of $\lesssim 0.25\sigma$ on each of the six
cosmological parameters. With the galaxy power spectrum alone, selection
effects can deteriorate the constraints severely, especially on the linear
growth rate. Adding the galaxy bispectrum helps break parameter degeneracies
significantly. We find that a joint power spectrum-bispectrum analysis of a
Euclid-like survey can still measure the linear growth rate to 10% precision
after complete marginalization over selection bias. We also discuss systematic
parameter shifts arising from ignoring selection effects and/or other bias
parameters, and emphasize that it is necessary to either control selection
effects at the percent level or marginalize over them. We obtain similar
results for the Roman Space Telescope and HETDEX.
