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6. Conclusions

We have selected a local sample of pairs of galaxies with the aim of building a photometric database which will be used in the future for comparing local pairs properties with more distant pairs. A few properties of local pairs that we have discussed in this paper are:

1) galaxies in close pairs are in general bluer than isolated galaxies,

2) close pairs of galaxies have an excess of early-type galaxies.

3) Late-type pairs show strong tidal damage to their morphology and blue star formation regions,

4) many elliptical galaxies in close pairs are in fact lenticular galaxies (2 lenticular galaxies have blue star formation regions),

5) pairs with smaller radial velocity difference present stronger signs of interaction,

6) pairs can present activity and tidal damage simultaneosly.

Moreover, one should take into account that local pairs of different morphology may have passed to a different evolution process which violently transformed their morphology. Pairs with at least one early-type component may be descendents of groups of galaxies, i.e. the early-type galaxy been already a result of a collapse of a group of galaxies. However, late-type pairs are probably long-lived showing clearly signs of interaction. Some of them could be seen as an early stage of mergers because they are still separated but with their disks very disturbed. One has also to account for the fact that more distant pairs could be in the process of formation and would have different properties when compared to these local pairs.


SJ and DFM thank CNPq for the fellowship and LI thanks Fondecyt Chile for support through "Proyeto FONDECyT 8970009" and from a 1995 Presidential Chair in Science. We are grateful to M.V. Alonso, N. Bergvall, W.C. Keel and J.M. Schwartzenberg for helpful comments and W. Freudling for providing GALPHOT. DFM thanks the hospitality at Universidad Catolica and ESO, Chile, and UNESCO for the international grant.

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