Small scale effects in the observable power spectrum at large angular
  scales
  In this paper we show how effects from small scales can enter the
angular-redshift power spectrum $C_\ell(z,z')$. In particular, we show that
spectroscopic surveys with high redshift resolution are already affected on
large angular scales, i.e. at low multipoles, by features from small scales.
When considering the angular power spectrum with spectroscopic redshift
resolution, it is therefore important to account for non-linearities relevant
on small scales, even at low multipoles. This may also motivate the use of the
correlation function in relatively wide redshift bins, which is not affected by
non-linearities on large scales, instead of the angular power spectrum. The
extent to which small-scale effects become visible on large scales, which is
more relevant for bin auto-correlations than for cross-correlations, is
quantified in detail.
