Scale-dependent bias induced by local non-Gaussianity: A comparison to N-body simulations
Nov, 2008
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Abstract: (arXiv)
We investigate the effect of primordial non-Gaussianity of the local type on the auto- and cross-power spectrum of dark matter haloes using a series of large N-body simulations of the LCDM cosmology. Theoretical models predict a scale-dependent bias correction \Delta b(k,f_NL) 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, on large scales (k < 0.01 h/Mpc), the theory and the simulations agree well for biased haloes with b(M)>1.5. At smaller scales, the effect in simulations is suppressed relative to theoretical predictions, in qualitative agreement with the expectations based on peak-background split. The suppression relative to the theory reaches a factor of three at k=0.1 h/Mpc. We give a fitting formula for it, which should be used when analysing observational data. The current limits on f_NL from Slosar et al. (2008) come mostly from very large scales and are only mildly affected. For the halo samples with b(M)<1.5 we find that the nonlinear bias from non-Gaussianity actually exceeds the theoretical predictions on very large scales, k <0.01 h/Mpc.Note:
- 10 pages, 8 figures. To be submitted to MNRAS
References(63)
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