Turnshek, David A.Wolfe, Arthur M.Lanzetta, Kenneth M.Briggs, Frank H.Cohen, Ross D.Foltz, Craig B.Smith, Harding E.Wilkes, Belinda2017-02-131989Turnshek, David A., Arthur M. Wolfe, Kenneth M. Lanzetta, Frank H. Briggs, Ross D. Cohen, Craig B. Foltz, Harding E. Smith, and Belinda J. Wilkes. 1989. “Damped Lyman-Alpha Absorption by Disk Galaxies with Large Redshifts. III - Intermediate-Resolution Spectroscopy.” The Astrophysical Journal 344 (September): 567. doi:10.1086/167827.0004-637Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:30212174New intermediate-resolution spectroscopy for six members of a sample of 68 moderate- to high-redshift QSOs is presented. Evidence is reported which indicates that seven strong absorption features in the QSO spectra are due to damped Ly-alpha absorption. A standard curve-of-growth analysis on five of the damped systems is performed, and relevant properties are tabulated and discussed. Six of the seven damped Ly-alpha systems have H I column densities of 2 x 10 to the 20th/sq cm or larger, while the remaining system has an H I column density of about 10 to the 20th/sq cm. It is suggested that damped Ly-alpha systems arise when a sight line intercepts a high-redshift protogalaxy disk containing a quiescent cloud component characterized by high column density and low effective velocity dispersion. At the same time, the sight line usually intercepts a broader turbulent component, which is identified as the halo, characterized by much lower column density and higher effective velocity dispersion.en-USAstronomical SpectroscopyDisk GalaxiesLyman Alpha RadiationQuasarsRed ShiftAbsorption SpectraAbundanceGalactic EvolutionLine SpectraJournal Article2017-02-1310.1086/167827