We briefly describe our on-going investigation of the near-IR luminosity-metallicity relationship for dwarf irregular galaxies in nearby groups of galaxies. The motivations of the project and the observational databases are introduced, and a preliminary result is presented. The 12 + log(O/H) vs. H plane must be populated with more low-luminosity galaxies before a definite conclusion can be drawn.

Adaptive Optics Systems are now routinely operated on several 4 meter class telescopes, allowing to achieve angular resolutions down to 70 msec in the near-infrared. Although these Systems have excellent performances, their use for exploring the physics and structure of AGN is still limited for the following reasons: the limiting magnitude of the wavefront sensor is too high, the sensitivity of infrared detectors does not give access to medium/high spectral resolution spectroscopy and the angular resolution achieved does not always fit the apparent size of the physical components responsible for emission features close to the central engine. The new generation of 8 — 10 m class telescopes bring improvements in this matter. However, some interesting results have been obtained so far with Adonis, the ESO La Silla adaptive optics System on the 3.60 meter telescope, in the investigation of AGN structure. In particular, a prominent structure has been detected in the central arcsec core of NGC 1068, which might feature the dusty/molecular torus expected on theoretical grounds.

We have analyzed a selection of globular clusters based on the indications of high metallicity from previous photometric studies.

We analyzed – in terms of age and metallicity – the stellar content of blue galaxies in 3 distant clusters at z ~ 0.3. We found that they contain a more metal-rich population than nearby late-type spirals.

We present the results of a monitoring campaign of the AGN in NGC 3227, conducted at La Palma by the LAG european consortium. The data are long slit spectra, obtained with the 1.5m INT and 4.2m WHT, from January to June 1990. The slit width was 1.5 arcsec. The spectral resolution was about 3 A.

We present recent analysis of star star clusters in M31

Recently, Jablonka, Alloin and Bica (1991) (herafter JAB) aimed at studying the properties of M31's star clusters and at enlarging the data base of star cluster integrated properties (Bica and Alloin, 1987) at high metallicities, for population synthesis purpose.

We have obtained spectra for 9 clusters in M31, 7 globular clusters, G1, G78, G158, G170, G177, G219, G222 and 2 open clusters, C107 and C130. Those spectra cover a wide wavelength range (3500å– 9800å) which allows one to confidently disentangle age, metallicity and reddening effects.

From continuum and line intensity light-curves in the ultraviolet range, we find that the CIV peak-emission lies at about 2 ± 0.5 light-month from the centre. Line profile variations in the Ha and CIV emission suggest that the BLR is made of two regions with distinct kinematical properties:

1. • a spherically distributed set of clouds, responsible for the broad HIL emission and responding to ionizing flux variations with a time-lag of 2 light-months at most

2. • a disc-like structure from which most of the LIL emission arises, with a slow response to ionizing flux changes: hence larger is size.

Many people have attacked the problem of synthesizing the stellar population of the galaxies. We have performed such a synthesis, by using only the intensities of absorption lines in the nuclei of galaxies. It is then possible to obtain a synthesized continuous spectrum even if there are several possible solutions for the stellar composition, and the computed continuum does not vary much with the assumed model of stellar population.

The method is to fit the equivalent widths of the absorption lines using different stellar compositions. In order to avoid any instrumental effect, we have observed different lines and bands from 3500 to 8500 å in stars of various well-known stellar types and luminosity classes, under the same conditions as the galaxies.

We have applied this method to some ‘ordinary’ nuclei and to some Seyfert ones. As an example, we show the results for M81 and for NGC 1068.