The Impact of Galaxies on their Environment from Observations of Gravitationally Lensed QSOs

Observations of absorption systems in close, multiple lines of sight to gravitationally lensed QSOs can be used to infer the density fluctuations and motions of the gas clouds giving rise to the Lyman α forest phenomenon and to QSO metal absorption systems. We describe a survey of lensed QSOs with the Keck HIRES instrument and argue that one can derive limits on the frequency and impact of hydrodynamical disturbances inflicted by galaxies on the surrounding gas from such data. We discuss differences between the kinematic properties of low density unsaturated Lyα forest absorption systems, high ionization CIV absorption systems, and low ionization gas visible in (e.g.) SiII and CII. The general intergalactic medium (as seen in the Lyα forest) shows very little turbulence, but the presumably denser CIV systems exhibit evidence of having been stirred repeatedly (by winds ?) in the past on time scales similar to those governing stellar feedback and possibly galaxy mergers. The quiescence of the low density IGM can be used to put upper limits on the incidence and energetics of galactic winds on a cosmological scale.