Strong clustering of high-redshift Ly alpha forest absorption systems

We use new observations of very weak C IV absorption lines associated with high-redshift Ly alpha absorption systems to measure the high-redshift Ly alpha line two-point correlation function (TPCF). These very weak C IV absorption lines trace small-scale velocity structure that cannot be resolved by Ly alpha absorption lines. We find that (1) high-redshift Ly alpha absorption systems with N(H I)> 3 x 10(13) cm(-2) are strongly clustered in redshift, (2) previous measurements of the Ly alpha line TPCF underestimated the actual clustering of the absorbers due to unresolved blending of overlapping velocity components, (3) the present observations are consistent with the hypothesis that clustering of Ly alpha absorption systems extends to lower column densities, but maybe with smaller amplitude in the correlation function, and (4) the observed clustering is broadly compatible with that expected for galaxies at z similar to 2-3. We interpret these results as suggesting that many or most Ly alpha absorbers may arise in galaxies even at high redshifts, and, therefore, that the Ly alpha forest probes processes of galaxy formation and evolution for redshifts z less than or similar to 5.