Large-scale structure in the Lyman- forest--II. Analysis of a group of 10 QSOs

The spatial distribution of Lyα forest absorption systems towards 10 QSOs is analysed to search for large-scale structure over the redshift range 2.2 99 per cent confidence level. In individual spectra we find overdense Lyα absorption on scales of up to 1200 km s−1. There is also strong evidence for correlated absorption across line-of-sight pairs separated by <3 h−1 proper Mpc (q0 = 0.5). For larger separations the cross-correlation signal becomes progressively less significant.