The Ultraviolet Spectrum of the Seyfert Galaxy NGC 4151

Spectra at 1·3 Å resolution of the spectral region λλ 3100–4000 have been obtained. Identifications and equivalent widths of emission lines are presented. The He I λ 3889 absorption varied by a factor 3·5 in 37 days and He I λ 3188 absorption was seen when λ 3889 was strong. The [ N I] line ratio λ 5199–3466 is consistent with $${n}_\text{e}\,\sim\,{10}^{4}\,\text{cm}^{-2}$$ in the region emitting the forbidden lines. Several short-wavelength lines are identified including the He II λ 3203 and several lines of [Fe V] multiplet 3F.