  With the advent of very large volume, wide-angle photometric redshift surveys
like e.g. Pan-STARRS, DES, or PAU, which aim at using the spatial distribution
of galaxies as a means to constrain the equation of state parameter of dark
energy, w_DE, it has become extremely important to understand the influence of
redshift inaccuracies on the measurement. We have developed a new model for the
anisotropic two point large-scale (r > 64 h^-1 Mpc) correlation function
xi(rp,pi), in which nonlinear structure growth and nonlinear coherent infall
velocities are taken into account, and photometric redshift errors can easily
be incorporated. In order to test its validity and investigate the effects of
photometric redshifts, we compare our model with the correlation function
computed from a suite of 50 large-volume, moderate-resolution numerical N-body
simulation boxes, where we can perform the analysis not only in real- and
redshift space, but also simulate the influence of a gaussian redshift error
distribution with an absolute rms of sigma_z= 0.015, 0.03, 0.06, and 0.12,
respectively. We conclude that for the given volume (V_box =2.4 h^-3 Gpc^3) and
number density (n ~ 1.25 10^-4) of objects the full shape of xi(rp,pi) is
modeled accurately enough to use it to derive unbiased constraints on the
equation of state parameter of dark energy w_DE and the linear bias b, even in
the presence of redshift errors of the order of sigma_z = 0.06.

Cosmology and Nongalactic Astrophysics