The correlation of the Lyman-alpha forest and metals in close pairs of   hight-redshift quasars
  We derive the transverse flux correlation function in the Lyman-alpha forest at z~2.1 from VLT-FORS observations of a total of 32 pairs of quasars. The shape and correlation length of the transverse correlation function are in good agreement with the paradigm of intergalactic medium predicted in CDM-like models for structures formation. Using a sample of 139 Civ systems detected along the lines of sight toward the pairs of quasars we investigate the transverse correlation of metals on the same scales. We find that the correlation function is consistent with that of a randomly distributed population of Civ systems. However, we detect an important overdensity of systems in front of a quartet. 
F. Coppolani, P. Petitjean, F. Stoehr, E. Rollinde, C. Pichon, S.   Colombi, M. Haehnelt, B. Carswell, R. Teyssier