Astron. Astrophys. 355, 949-965 (2000)

8. Conclusions

We demonstrate how deep images with high spatial resolutions, only available since the advent of HST, enable us to determine the properties of the Galactic Bulge stellar population(s). In this we have used three measures;

• number counts - to search for a young stellar population

• histograms - to search for a metal-rich population

• comparison of ridge lines - to derive metallicities and look for internal differences, i.e. gradients in age and metallicity

In particular we find that

• our results are consistent with no significant young stellar population in the Bulge, some 500pc, or 2-5 scale lengths, from the centre, contrary to some previous studies;

• the Galactic Bulge has a mean metallicity equal to that of the old disk;

• there is marginal evidence for a central metallicity gradient;

• the colour-magnitude diagram of NGC6553 is complex, requiring care in photometric analyses of this cluster.

© European Southern Observatory (ESO) 2000

Online publication: March 21, 2000
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