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D. S. Rupke, S. Veilleux (U. of Maryland), D. B. Sanders (IfA, U. of Hawaii)
We use moderately-high resolution spectroscopy from ESI on Keck II to probe the properties of the cool, absorbing gas in massive outflows in a sample of ultraluminous infrared galaxies (ULIGs) at z < 0.3. Measured mass outflow rates are comparable to the corresponding global star formation rates (SFRs) inferred from infrared luminosities, a result also obtained in less massive galaxies. This implies that the mass outflow rates of star-forming galaxies, normalized to the corresponding global star formation rates, are fairly constant over a large range of SFR. Using kinematics inferred from line widths, we also measure a high escape fraction for the gas (~0.5). If these results apply at z > 0.3, ULIGs may supply a significant fraction of the gas being expelled by star-forming galaxies into the intergalactic medium at higher z.
SV and DSR acknowledge support from a Cottrell Scholarship awarded by the Research Corporation, a NASA/LTSA grant, and an NSF/CAREER grant.