Synergistic Astrophysics in the Ultraviolet using Active Galactic Nuclei
  Observing programs comprising multiple scientific objectives will enhance the productivity of NASA's next UV/Visible mission. Studying active galactic nuclei (AGN) is intrinsically important for understanding how black holes accrete matter, grow through cosmic time, and influence their host galaxies. At the same time, the bright UV continuum of AGN serves as an ideal background light source for studying foreground gas in the intergalactic medium (IGM), the circumgalactic medium (CGM) of individual galaxies, and the interstellar medium (ISM) and halo of the Milky Way. A well chosen sample of AGN can serve as the observational backbone for multiple spectroscopic investigations including quantitative measurements of outflows from AGN, the structure of their accretion disks, and the mass of the central black hole. 
Gerard Kriss (1), Nahum Arav (2), Anton Koekemoer (1), Smita Mathur   (3), Bradley M. Peterson (3) and Jennifer E. Scott (4)...
astro-ph.CO