Microwave backgropund anisotropies, large-scale structure and cosmological parameters

Abstract

We review how the various large-scale data constrain cosmological parameters and, consequently, theories for the origin of large-scale structure in the Universe. We discuss the form of the power spectrum implied by the correlation data of galaxies and argue by comparing the velocity field implied by the distribution of light with the observed velocity flows that the bias parameter, $b$, is likely to be constant in the linear regime. This then allows one to estimate the density parameter, $Ω$, and $b$ directly from the \underline{data} on $ξ(r)$ and the velocity fields. We show that it is consistent with low values of $Ω^{0.6}/b$. We discuss the ways to normalise the optical data at $z\sim0$ directly to the COBE (or other microwave background) data. The data on high-$z$ \underline{galaxies} allows one to further constrain the shape of the \underline{primordial} power spectrum at scales which are non-linear today ($< 8h^{-1}$Mpc) and we discuss the consistency of the data with inflationary models normalised to the large-scale structure observations.