Gravitational clustering from χ² initial conditions

We consider gravitational clustering from primordial non-Gaussian fluctuations provided by a χ² model, as motivated by some models of inflation. The emphasis is on signatures that can be used to constrain this type of model from large-scale structure galaxy surveys. Non-Gaussian initial conditions provide additional nonlinear couplings otherwise forbidden by symmetry that cause nonlinear gravitational corrections to become important at larger scales than in the Gaussian case. In fact, the lack of hierarchical scaling in the initial conditions is partially restored by gravitational evolution at scales k > 0.1 h Mpc^-1. However, the bispectrum shows much larger amplitude and residual scale dependence not present in evolution from Gaussian initial conditions, which can be used to test this model against observations. We include the effects of biasing and redshift distortions essential to compare this model with galaxy redshift surveys. We also discuss the effects of primordial non-Gaussianity on the redshift-space power spectrum and show that it changes the shape of the quadrupole to monopole ratio through nonlinear corrections to infall velocities.