Far-Ultraviolet Spectra of AGN: First Results from FUSE

Abstract

Composite spectra derived from HST observations of moderate redshift (z~1) quasars show that the peak of the spectral energy distribution is at ~1000 A, and that the ionizing continuum falls off smoothly to shorter wavelengths as $f_ν\sim ν^{-1.8}$. HUT and FUSE observations of nearby AGN (e.g., 3C 273) show similar results. FUSE spectra reveal a wealth of detail in the 912-1200 A spectral range, including multi-component intrinsic absorption in the O VI doublet and Lyb, and surprisingly strong narrow-line emission from O VI 1032,1038. Monitoring observations of AGN below 1200 A are feasible, and such experiments could help to unravel the structure of intrinsic absorbers in AGN as well as the highest ionization portions of the broad-line region.