We present Cosmic Origins Spectrograph ( COS ) measurements of metal abundances in eight 0.083 < z _ { abs } < 0.321 damped Lyman- \alpha ( DLA ) and sub-damped Ly \alpha absorption systems serendipitously discovered in the COS-Halos survey .
We find that these systems show a large range in metallicities , with -1.10 < [ Z / H ] < 0.31 , similar to the spread found at higher redshifts .
These low-redshift systems on average have subsolar metallicities , but do show a rise in metallicity over cosmic time when compared to higher-redshift systems .
We find the average sub-DLA metallicity is higher than the average DLA metallicity at all redshifts .
Nitrogen is underabundant with respect to \alpha -group elements in all but perhaps one of the absorbers .
In some cases , [ N/ \alpha ] is significantly below the lowest nitrogen measurements in nearby galaxies .
Systems for which depletion patterns can be studied show little , if any , depletion , which is characteristic of Milky Way halo-type gas .
We also identify affiliated galaxies for 3 of the sub-DLAs using spectra obtained from Keck/LRIS .
None of these sub-DLAs arise in the stellar disks of luminous galaxies ; instead , these absorbers may exist in galaxy halos at impact parameters ranging from 38 to 92 kpc .
Multiple galaxies are present near two of the sub-DLAs , and galaxy interactions may play a role in the dispersal of the gas .
Many of these low-redshift absorbers exhibit simple kinematics , but one sub-DLA has a complicated mix of at least 13 components spread over 150 km s ^ { -1 } .
We find three galaxies near this sub-DLA , which also suggests that galaxy interactions roil the gas .
This study reinforces the view that DLAs have a variety of origins , and low-redshift studies are crucial for understanding absorber-galaxy connections .