Unformatted text preview: AAS): Lanzetta found that these systems seem to have constant comoving space density, and that the Mg II metal-line systems seem to be disappearing relative to Lyman-limit systems. These systems may also be sought in BL Lac objects, avoiding confusion with emission-line or BAL structure but introducing the problem that we may not know the AGN redshift except as the redshift at which the Lyman α forest disappears....
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- Fall '10
- Astronomy, Quasar, Lyman edge, Lyman limit absorber