Measuring equality horizon with the zero-crossing of the galaxy correlation function

Abstract

The size of the horizon at the matter-radiation equality is a key scale of the Big Bang cosmology that is directly related to the energy-matter content of the Universe. In this letter, we argue that this scale can be accurately measured from the observed clustering of galaxies in new large scale surveys. We demonstrate that the zero-crossing, r_c, of the 2-point galaxy correlation function is closely related to the horizon size at matter-radiation equality for a large variety of flat LCDM models. Using large-volume cosmological simulations, we also show that the pristine zero-crossing is unaltered by non-linear evolution of density fluctuations, redshift distortions and galaxy biases. This makes r_c a very powerful standard ruler that can be accurately measured, at a percent level, in upcoming experiments that will collect redshifts of millions of galaxies and quasars.

4 pages, 4 figures

Cited by in corpus (7)

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• Current constraints on deviations from General Relativity using binning in redshift and scale
• The redshift-space galaxy two-point correlation function and baryon acoustic oscillations
• Measurement of the matter-radiation equality scale using the extended Baryon Oscillation Spectroscopic Survey Quasar Sample