A Study of Damped Ly$\alpha$ Absorption Systems with the MMT Red Spectrograph
Session 18 -- AGN Spectroscopy
Display presentation, Monday, 9, 1995, 9:20am - 6:30pm

## [18.06] A Study of Damped Ly$\alpha$ Absorption Systems with the MMT Red Spectrograph

J.Saucedo, J.Bechtold (Steward Observatory)

Moderate resolution spectra of 6 quasars obtained with the Red Spectrograph at the Multiple Mirror Telescope (MMT) are presented. The quasars contain foreground damped or candidate damped Ly$\alpha$ systems ranging in redshift from 1.95 to 3.39. In a few cases, we fit the Ly$\alpha$ absorption lines with Voigt profiles in order to determine the {H I} column densities. A few comments are made about the quality of the fits with regard to the damping nature of the absorbers. \par We perform a curve of growth analysis for the metal lines associated with the damped systems. Our results are then compared to those obtained by similar studies for high redshift damped systems and with well studied interstellar clouds in our Galaxy. We find that the average abundances relative to hydrogen of O I, C II, Si II, Fe II and Al II in damped Ly$\alpha$ systems resemble those of the Galactic Halo. On the other hand, the mean values of C I/H I and CO/H I are much smaller than those seen in interestellar clouds toward $\zeta$ Oph.