  As a major source of cosmological information, galaxy clustering is
susceptible to long-wavelength density and tidal fluctuations. These long modes
modulate the growth and expansion rate of local structures, shifting them in
both amplitude and scale. These effects are often named the growth and dilation
effects, respectively. In particular the dilation shifts the baryon acoustic
oscillation (BAO) peak and breaks the assumption of the Alcock-Paczynski (AP)
test. This cannot be removed with reconstruction techniques because the effect
originates from long modes outside the survey. In redshift space, the long
modes generate a large-scale radial peculiar velocity that affects the
redshift-space distortion (RSD) signal. We compute the redshift-space response
functions of the galaxy power spectrum to long density and tidal modes at
leading order in perturbation theory, including both the growth and dilation
terms. We validate these response functions against measurements from simulated
galaxy mock catalogs. As one application, long density and tidal modes beyond
the scale of a survey correlate various observables leading to an excess error
known as the super-sample covariance, and thus weaken their constraining power.
We quantify the super-sample effect on BAO, AP, and RSD measurements, and study
its impact on current and future surveys.
