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