The Hubble Space Telescope Quasar Absorption Line Key Project XIII. A Census of Absorption Line Systems at Low Redshift

摘要

We present a catalogue of absorption lines obtained from the analysis of theultra-violet spectra of 66 quasars. The data were acquired with the FaintObject Spectrograph of the HST as part of the Quasar Absorption Line Survey, aKey Project for the first four cycles of HST observations. This is the third ofa series of catalogues of absorption lines produced from the survey andincreases the number of quasars whose higher resolution (R=1300) spectra wehave published from 17 to 83. The general properties and execution of thesurvey are reviewed, including descriptions of the final sample of observedobjects and the algorithmic processes used to construct the catalogue. Thedetection of a single damped Ly-a system in a path length of Delta_z=49 yieldsan observed number of damped systems per unit redshift of(dN/dz)_{damp}(z=0.58)=0.020 with 95% confidence boundaries of 0.001 to 0.096systems per unit redshift. We include notes on our analysis of each of theobserved quasars and the absorption systems detected in each spectrum. Someespecially interesting systems include low redshift Ly-a absorbers suitable forextensive follow-up observations (in the spectra of TON28 and PG1216+069),possibly physically associated pairs of extensive metal line absorption systems(e.g., in the spectrum of PG0117+213), and systems known to be associated withgalaxies (e.g., in the spectrum of 3C232).