Discovery of [CLC][ITAL]z[/ITAL][/CLC] = 0.0912 and [CLC][ITAL]z[/ITAL][/CLC] = 0.2212 Damped L[CLC]y[/CLC]α Absorption-Line Systems Toward the Quasar OI 363: Limits on the Nature of Damped L[CLC]y[/CLC]α Galaxies

The discovery of a z abs =0.0912 damped Lyα absorption-line system in the Hubble Space Telescope Faint Object Spectrograph ultraviolet spectrum of the quasar OI 363 (0738+313) is reported. This is the lowest redshift quasar-damped Lyα system known. Its neutral hydrogen column density is N (H I) =1.5 ± 0.2 × 10 21 atoms cm -2 , which easily exceeds the classical criterion for damped Lyα of N (H I) ≥2 × 10 20 atoms cm -2 . Remarkably, a z abs =0.2212 damped system with N (H I) =7.9 ± 1.4 × 10 20 atoms cm -2 has also been discovered in the same spectrum. In the past, the standard paradigm for damped Lyα systems has been that they arise in galactic or protogalactic H I disks with low impact parameters in luminous galaxies. However, WIYN imaging of the OI 363 field shows that none of the galaxies visible in the vicinity of the quasar is a luminous gas-rich spiral with low impact parameter, either at z =0.0912 or z =0.2212. Thus, these damped systems are among the clearest examples yet of cases that are inconsistent with the standard damped Lyα-H I-disk paradigm.