Scale-dependent bias induced by local non-Gaussianity: a comparison toN-body simulations

We investigate the effect of primordial non-Gaussianity of the local fNL type on the auto- and cross-power spectrum of dark matter haloes using simulations of the LCDM cosmology. We perform a series of large N-body simulations of both positive and negative fNL, spanning the range between 10 and 100. Theoretical models predict a scale-dependent bias correction Δb (k, fNL) that depends on the linear halo bias b (M). We measure the power spectra for a range of halo mass and redshifts covering the relevant range of existing galaxy and quasar populations. We show that auto and cross-correlation analyses of bias are consistent with each other. We find that for low wavenumbers with k1. 5. We show that a scale-independent bias correction improves the comparison between theory and simulations on smaller scales, where the scale-dependent effect rapidly becomes negligible. The current limits on fNL from Slosar et al. (2008) come mostly from very large scales k<0. 01 h/Mpc and, therefore, remain valid. For the halo samples with b (M) <1. 5-2 we find that the scale- dependent bias from non-Gaussianity actually exceeds the theoretical predictions. Our results are consistent with the bias correction scaling linearly with fNL.