6 Concluding remarks

We point out that in the bulge regions we are dealing with very reddened globular clusters, contaminated by rich bulge/disk fields. The contamination affects more integrated studies than CMDs. On the other hand, since stars of different temperatures are affected differentially by effective passband variations due to reddening (Grebel & Roberts 1995), CMD distortions are expected. We estimate that the trend will be in the sense of causing steeper RGBs. In order to get a conclusive result on the metallicity, it is required that spectroscopy of individual giants of these clusters be carried out with large telescopes.

Terzan 9, NGC 6139 and NGC 6453 are spatially located within the bulge volume. Since they appear to be metal-poor, it is not clear whether they belong to the bulge or halo population. Kinematical data would help constrain this issue.

In addition to the results for Terzan 9, NGC 6139 and NGC 6453, a series of recent CCD photometries of clusters towards the bulge showed that an important sample has blue horizontal branches, namely HP 1 (Ortolani et al. 1997), NGC 6522 (Barbuy et al. 1994; Terndrup & Walker 1994, Shara et al. 1998), NGC 6540 (Bica et al. 1994), NGC 6558 (Rich et al. 1998), NGC 6256 and NGC 6717 (Ortolani et al. 1999). On the other hand, the clusters Tonantzintla 2 (Bica et al. 1996), NGC 6380 and Terzan 12 (Ortolani et al. 1998), Terzan 3 and IC 1276 (Palomar 7) (Barbuy et al. 1998b), also located in the ring $5^\circ<r<20^\circ$ surrounding the central parts of the Galaxy, show a red horizontal branch (RHB) morphology. In the literature a number of clusters in the region have been studied by means of CCD, such as five RHB ones by Armandroff (1988).

We point out that most of the BHB clusters appear to have intermediate metallicities ($-1.5<{\rm [Fe/H]}<-1.0$), which we considered to form a family as discussed in Bica et al. (1998) and Rich et al. (1998). NGC 6517 with ${\rm [Fe/H]}=-1.58$ also has a BHB (Kavelaars et al. 1995). NGC 6287 (Stetson & West 1995), Terzan 4 (Ortolani et al. 1997a) and the present clusters Terzan 9, NGC 6139 and NGC 6453 seem to be in the very metal-poor class (${\rm [Fe/H]}\approx -2.0$). A fundamental question is which ones belong to the bulge or halo. In any case, spectroscopic studies of individual stars combined to proper motion determinations for all the blue HB sample are crucial to understand the early stages of the halo and bulge formation and evolution.

Acknowledgements

BB and EB acknowledge partial financial support from CNPq and Fapesp.