Abstract. Most Seyfert 1 galaxies show strong Fe II lines in their spectrum having the velocity and width of the broad emission lines. To remove the Fe II contribution in these objects, an accurate template is necessary. We used very high signal-to-noise, medium resolution archive optical spectra of I Zw 1 to build such a template. I Zw 1 is a bright narrow-line Seyfert 1 galaxy. As such it is well suited for a detailed analysis of its emission line spectrum. Furthermore it is known to have a very peculiar spectrum with, in addition to the usual broad and narrow line regions, two emission regions emitting broad and blue shifted [O III] lines making it a peculiarly interesting object. While analysing the spectra, we found that the narrow-line region is, unlike the NLR of most Seyfert 1 galaxies, a very low excitation region dominated by both permitted and forbidden Fe II lines. It is very similar to the emission spectrum of a blob in η Carinae which is a low temperature (T e ∼ 6500 K), relatively high density (N e = 10 6 cm −3 ) cloud. The Fe II lines in this cloud are mainly due to pumping via the stellar continuum radiation field (Verner et al. 2002). We did not succeed in modelling the spectrum of the broad-line region, and we suggest that a non radiative heating mechanism increases the temperature in the excited H I region, thus providing the necessary additional excitation of the Fe II lines. For the low-excitation narrow-line region, we are able to apply boundaries to the physical conditions accounting for the forbidden and permitted Fe II lines (10 6 < N e < 10 7 cm −3 ; 10 −6 < U < 10 −5 ).

This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of the spectra and evolution of galaxies. A broad variety of empirical and theoretical data are discussed here, and the data are made fully available in the AAS CD-ROM Series, Vo. 7. Several empirical stellar libraries are part of this database. They cover the ultraviolet spectral range observed with IUE, optical data from different ground-based telescopes, and ground-based infrared data. Spectral type coverage depends on the wavelength, but it is mostly complete for types O and M and luminosity classes V to I. A large metallicity range is covered as well. Theoretical libraries of selected spectral indices of cool stars and of stellar continuum fluxes in the temperature range 2000 K to 50,000 K, as well as Wolf-Rayet energy distributions are presented. Several libraries of star clusters and early-type galaxies have been selected for this database. We discuss an extensive set of empirical spectra templates covering the wavelength region from 1200 - 9800 A, as well as narrow-band line indices in a large number of passbands. Bench-mark spectra of nearby galaxies for model tests are included as well. We compiled numerous evolutionary models and isochrones for stars of all mass ranges of interest, wide metallicity range, and for all evolutionary phases, including the pre-main-sequence phase. The majority of the models have been computed by the Geneva and Padova groups. Evolutionary synthesis models computed by several independent groups are made available. They can be applied to old and young systems, and are optimized with respect to different aspects of input physics. The model predictions include stellar (colors, magnitudes, absorption features) and nebular (emission-line fluxes) properties. Finally, we present models of ionized gas to be used for the interpretation of active galactic nuclei and young star-forming galaxies. The community is encouraged to make use of this electronic database and to perform a critical comparison between the individual datasets

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Abstract. -A sample of 37 stars of luminosity classes I, III, V, including few SMR stars observed in the H band with a medium resolution (R=1500−2000) is presented. This sample of flux calibrated spectra is intended to widen existing stellar libraries. A new IR spectrograph, ISIS/IR, foreseen for CFHT has been used. Its main characteristics are briefly described. Stellar spectra obtained with this new spectrograph are compared to similar data obtained with the ESO NTT IRSPEC spectrograph. The behaviour of some prominent features is described and it is shown that the COλ1.60/SiIλ1.60 line ratio is a good luminosity indicator for stellar types later than K0.

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The narrow-line Seyfert 1 galaxy IRAS 07598+6508 is known to be a stong Fe II emitter. The analysis of several high S/N ratio spectra shows that its spectrum is dominated by a relatively narrow "broad line" region (1780 km s −1 FWHM) emitting not only Fe II, but also Ti II and Cr II lines. Although we were unable to find a completely satisfactory physical model, we got the best agreement with the observations with collisional rather than radiative models, with a high density (n = 10 15 cm −3 ), a high column density (N H = 10 25 cm −2 ) and a microturbulence of 100 km s −1 . This BLR is qualitatively similar to the one observed in I Zw 1. We have not found traces in IRAS 07598+6508 of the narrow line regions found in I Zw 1.

Abstract. In this paper we apply the stellar population synthesis method previously described in Boisson et al. (2000) to five more AGN. The analysis of these new data strengthen our previous conclusions: i) homogeneity of the stellar population within a class of nuclear activity regardless of the morphological type of the host galaxy; ii) populations within the nuclear regions of LINERs and Seyfert 2s are different: LINERs have a very old metal-rich population while in the Seyfert 2s a contribution of a weak burst of star formation is observed together with the old high metallicity component; iii) in the circum-nuclar region (200 pc ≤ D ≤ 1 kpc) of all the active galaxies in our sample, except for NGC 2992, we detect an old burst of star formation (0.2−1 Gyr),which is contrary to what is observed in normal galaxies. We note that the broad OIλ8446 Å emission line detected in the spectrum of the nucleus of NGC 2992 confirms its classification as a Seyfert 1.

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