The real-space power spectrum of the PSCz survey from 0.01 to 300h Mpc-1

We report a measurement of the real-space (not redshift-space) power spectrum of galaxies over four and a half decades of wavenumber, 0.01 to 300hMpc^-1, from the IRAS Point Source Catalog Redshift Survey (PSCz). Since estimates of power are highly correlated in the non-linear regime, we also report results for the pre-whitened power spectrum, which is less correlated. The inferred bias between optically selected APM and IRAS-selected PSCz galaxies is about 1.15 at linear scales <~0.3hMpc^-1, increasing to about 1.4 at non-linear scales >~1hMpc^-1. The non-linear power spectrum of PSCz shows a near power-law behaviour to the smallest scales measured, with possible mild upward curvature in the broad vicinity of k~2hMpc^-1. Contrary to the prediction of unbiased dark matter models, there is no prominent inflection at the linear to non-linear transition scale, and no turnover at the transition to the virialized regime. The non-linear power spectrum of PSCz requires scale-dependent bias: all Dark Matter models without scale-dependent bias are ruled out with high confidence.