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Stellar Population content in the Local Group Galaxies and beyond

The recent great attack of the last generation Telescopes such as the NTT and the HST provided fundamental constraints concerning the evolutionary properties of stellar populations belonging to the Magellanic Clouds, the Magellanic Stream, and some Local Group Galaxies (LGG). However, during the next ten years this large observational effort should be put forward since we need to strengthen and widen the observational data concerning both metal-poor and metal-rich stellar population content in members of group of galaxies such as Sculptor, M81, M66-M96, M31, M33, and Centaurus. The reader interested in a detailed discussion of the present observational scenario of LGG is referred to the comprehensive review by van den Bergh (1992, PASP, 104, 861).

It is worth noting that even though some investigations have been recently devoted to the Color-Magnitude diagram of stellar systems in the quoted clusters, up to now we lack a detailed analysis of the evolutionary properties (age, chemical composition, spatial distribution) of field stars in the halo and/or in the bulge of these galaxies. A detailed map of all the stellar populations in nearby galaxies is of great importance for the population synthesis analysis, etc.

The LBT prime focus equipped with a large CCD camera can provide an extensive investigation of bright low-mass stars (RGB, AGB), intermediate and high mass stars by measuring accurately large stellar fields in different photometric bands. This allows to collect statistically significant samples of stars at any evolutionary status, providing fundamental inputs for both the star formation and the stellar evolution theories. The C-M diagram of large extragalactic stellar fields together with the kinematic properties can cast new light on several astrophysical problems concerning the chemical evolution, the star formation and the metallicity gradients in galaxies which experienced a different dynamical evolutions and environment effects when compared to our Galaxy.

We need to combine large field coverage with the capability to reach (at least in the galaxy outskirts) the horizontal branch. This means a limiting magnitude of at least V=26.6-27 for the galaxies in the outskirts of the Local Group. Only a prime focus imager at LBT can allow this kind of observations. In order to be able to study galaxies with different morphological types, we need to go also beyond the Local Group (in groups as Sculptor, M81-MGC 2403 etc.). Again, in order to completely map the galaxies in these groups we need large fields and push the limiting magnitude to V=27 or beyond.


next up previous contents
Next: Primary Distance Indicators Up: Stellar populations Previous: Mass segregation in open
Guido Buscema
1999-01-29