This second title in the series published for the Space Telescope Science Institute researches the current models of quasar absorption and the systems of absorp

The controversial question of whether the majority of the narrow absorption lines observed in QSO spectra represent cosmological intervening systems or ejecta f

Review of recent research in the field of quasar absorption line systems.

How can we test if a supermassive black hole lies at the heart of every active galactic nucleus? What are LINERS, BL Lacs, N galaxies, broad-line radio galaxies