Structure Formation in the Universe

Abstract

We report a detection of galaxy-QSO cross-correlation ωGQ in the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR). We cross-correlate galaxy samples of different mean depths r’ = 19−22 ($\bar z$ _G = 0.15−0.35) with the main QSO population (i’ _Q < 19.2) at $\bar z$ _Q ≃ 1.6. The amplitude of the signal on arc-minute scales is about 10–20%. This is a few times larger than currently expected from structure formation ACDM models on arc-minute scales, but confirms, at a higher significance, previous measurements by several groups. The observations can be reconciled with flat A universe with σ₈ ≃ 1 provided the linear spectrum is steeper (n ≃ 1) than in the ACDM model on small (cluster) scales. The galaxy distribution are anti-bias with b = 0.1 on small scales, increasing with scale to b = 1 at 10 Mpc/h.