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H.-W. Chen (Carnegie Observatories)
I present a study of the galaxies that give rise to Lyman-\alpha (Ly\alpha) and triply ionized carbon (C\,IV) absorption lines observed in the spectra of background quasi-stellar objects. By comparing the redshifts of galaxies and Ly\alpha absorption systems along common lines of sight, I confirmed the existence of an anti-correlation between Ly\alpha absorption equivalent width and galaxy impact parameter. Further analysis showed that the extent of tenuous gas scales with galaxy B-band and K-band luminosities. I found that extended gaseous halos are a common and generic feature of galaxies over a wide range of luminosity and morphological type and Ly\alpha absorption systems traced a significant and representative portion of the galaxy population. By comparing the redshifts of galaxies and C\,IV absorption systems along common lines of sight, I also found that extended gaseous halos of galaxies have been enriched by metals out to large galactocentric radii, \approx 100\ h-1 kpc. The covering factor of ionized gas in galactic halos was estimated to nearly unity.
The author(s) of this abstract have provided an email address for comments about the abstract: hchen@ociw.edu