Time scales of dynamical processes in the intergalactic medium

Measurements of absorption pattern differences produced by high redshift galactic and intergalactic gas on multiple lines of sight to gravitationally-lensed QSOs can be used to investigate the nature and time scales of hydrodynamic disturbances in early galaxies and the intergalactic medium (IGM). The relative differences between the absorption systems as a function of projected separation on the sky constrains the rate of energy input into the IGM and the frequency of recurrent star forming events at high redshift. Both the amplitude of the turbulence and the coherence length of the clouds are consistent with the clouds being produced, stirred, or destroyed by star formation or merger-triggered gasdynamics on a time scale of 10(7)-10(8) yr. The results are based on a survey of absorption systems in lensed z similar to 3 QSOs with Keck HIRES.