On the Growth Rate of the Correlation Function of Faint Galaxies

Abstract

We constrain the growth rate of structure, as represented by the spatial two-point galaxy auto-correlation function, at redshifts where this has not yet been measured directly by combining recent measurements of the amplitude of the angular two-point galaxy auto-correlation, at magnitudes as faint as V_median ≤ 25, with new observations of the redshift distribution of very faint galaxies. We show that ξ for the overall galaxy population (at a fixed proper separation r) grows (1 + z)^4±1 times as fast as clustering which is fixed in proper coordinates. Even extreme models where “blue” galaxies have a smaller, IRAS-like, correlation function do not reduce the growth rate below (1 + z)^{2 5±1} times the clustering fixed in proper coordinates (Roukema, B.F. and Valls-Gabaud, D. (1995) A&A, submitted).