AAS 197, January 2001
Session 3. QSO Absorbers and the IGM
Display, Monday, January 8, 2001, 9:30am-7:00pm, Exhibit Hall

## [3.12] Low Ionization Gas in Galaxies: Keck HIRES Spectra of Ten QSO Absorption Systems with Ca II and Na I Lines

V. T. Junkkarinen, R. D. Cohen (UCSD/CASS)

We have obtained Keck HIRES spectra of ten z < 0.1 quasar absorption systems that show Ca~II \lambda\lambda3934,3968 and/or Na~I \lambda\lambda5890,5896 absorption. The sample includes several well known QSO--galaxy pairs, and is almost complete for z < 0.1 quasar absorption systems with detected Ca~II and/or Na~I. These high resolution (~ 7 km s-1 FWHM) observations are useful for measuring the column densities and velocity widths in the multi--component absorbers. The number of velocity components varies from one in the least complex absorber to about 13 in the most complex absorber. Five of the ten systems show components with N(Na~I) / N(Ca~II) > 1.0, a high'' ratio typically interpreted, in our Galaxy, to be the result of depletion of Ca onto dust grains. These quasar absorbers also show a tendency for the narrower components to coincide with high values of N(Na~I) / N(Ca~II) which is also the observed tendency in the Galaxy. Several of these absorbers are probably damped Ly\alpha (DLA) systems based on strong H~I 21 cm absorption and/or H~I 21 cm emission maps of the absorbing galaxies that show a high average H~I column (N(H~I) \ge 2.0 \times 1020 cm-2) at the quasar line of sight. These data are indirect evidence for dust in low z DLA systems and suggest that the dust content varies widely from component to component. Galaxies with normal morphologies and galaxies with disturbed morphologies both contribute absorbers in this sample. Gas that is disk--like,'' based on a high N(Na~I) / N(Ca~II) ratio, can be present in tidally distorted structures as well as galaxy disks.