The ultraviolet spectra of active galaxies with weak optical Fe II lines.

Abstract

The authors have obtained simultaneous optical and IUE spectra of two Seyfert galaxies that show very weak optical Fe II lines: Mrk 290 and Mrk 915. IUE archival spectra of the radio galaxy 3C 390.3 are also compared with optical data obtained during the same year. Strong, distinct ultraviolet features are observed in the spectrum of Mrk 290. A fit to all spectral features between 1900 and 5500 Å includes several thousand Fe II lines, many Balmer lines, Balmer continuum, and metallic lines. Evidence for strong ultraviolet Fe II lines is found also in 3C 390.3, and the case of Mrk 915 is inconclusive. This paper demonstrates several new aspects of the spectra of active galactic nuclei, especially the large amount of energy emitted by Fe II lines and the possible importance of dust or very high density clouds or both in such objects.