Detailed observations of NGC 4151 with the IUE - IV. Absorption line spectrum and variability.
Tanzi, E. G.; Perola, G. C.; Boksenberg, A.; Penston, M. V.; Snijders, M. A. J.; Bromage, G. E.; Clavel, J.; Elvius, A.; Ulrich, M. H.; Pettini, M.
United Kingdom, France, Sweden, Italy, Germany
Abstract
A detailed analysis is presented of the ultraviolet (λλ1150 - 3200 Å) absorption spectrum of the NGC 4151 Seyfert nucleus. The IUE data base consisted of high-dispersion (Δλ ≡ 0.2 Å) spectra at 5 epochs, and 137 low-dispersion (Δλ ≡ 4 - 8 Å) spectra at 31 epochs from 1978 February to 1980 May, together with further low-dispersion data in 1980 - 81 with NGC 4151 in a very faint quiescent state.