IAU02768
Presentation type requested: ORAL
OBSERVING THE IMPACT OF GALAXIES ON THE INTERGALACTIC MEDIUM
Kurt Adelberger
CfA
The presence of metals in the intergalactic medium (IGM) shows that much of the universe must have been roiled by supernova-driven blastwaves at some early time. I will discuss recent observations that suggest that some of these blastwaves were produced by galaxies at relatively low redshifts, z~2-3. Galaxies at these redshifts are generally driving their interstellar material outwards at several hundred km/s. Their mass-loss rates are comparable to their star-formation rates. Comparing the locations of HI and metal absorption lines in the spectra of background QSOs to the positions of foreground Lyman-break galaxies (LBGs) shows that star-forming galaxies at z~2-3 tend to be surrounded by metal-enriched material but often have less HI within 0.5 comoving Mpc than predicted by numerical simulations that neglect the effect of blastwaves on galaxies' surroundings. Many of the observations are qualitatively consistent with a picture in which high- redshift galaxies' observed outflows are able to penetrate nearly 1 comoving Mpc into the surrounding intergalactic medium.
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