Abstract

We investigate the 3-D matter distribution at z ? 2 with high resolution (R ? 40, 000) spectra of QSO pairs and groups obtained with the UVES spectrograph at ESO VLT. Our sample is unique for the number density of objects and the variety of separations, between ? 0.5 and 7 proper Mpc†. We compute the real space cross-correlation function of the Lyman-? forest transmitted fluxes. There is a significant clustering signal up to ?2 proper Mpc, which is still present when absorption lines with high column density (log N ? 13.8) are excluded. © 2005 International Astronomical Union.