Where the Very Bright Matter is a Standard Ruler

Abstract

Where's the matter? The answer seems to be: ``distributed according to a power spectrum with at least one feature (local maximum) near 120-130h^-1Mpc''. Analyses of the Iovino, Clowes & Shaver quasar candidate catalogue at z~2 and the 2dF Quasar Survey 10K Release (2QZ-10K) support this claim, which has previously been made both for low redshift survey analyses and for high z~3) redshift surveys will be presented. This feature (i) offers a comoving standard ruler which can lift the matter density-cosmological constant (Omega_m-Omega_Lambda) degeneracy and (ii) might be due either to baryonic acoustic oscillations or to Planck epoch physics which survives through inflation. (i) The 95% confidence constraint from the 2QZ-10K is Omega_m= 0.25\pm0.15, Omega_Lambda=0.60{\pm0.35}. This constraint is independent of cosmic microwave background constraints and type Ia supernovae constraints. The only assumptions required are (a) that the Universe satisfies a perturbed Friedmann-Lema\^ıtre-Robertson-Walker model with a possibly non-zero cosmological constant, (b) that the density perturbations in this model on large scales (>> 10h^-1Mpc) remain small (``linear'') and approximately spatially fixed in comoving coordinates, (c) that the statistics (power spectrum or correlation function) of the perturbations are redshift independent, and (d) that quasar redshifts are cosmological.