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Astron. Astrophys. 347, 55-62 (1999) 6. ConclusionsIn this paper we have studied the stellar population, nuclear emission and the presence of AGN in a sample of 27 physical galaxy pairs. The main conclusions can be summarised as follows: (i) The stellar population analysis based on equivalent
widths of absorption lines and continuum distribution shows that about
half of the bulges of the A components have a very red stellar
population and solar abundance, while more than 70% of the B
components have an important flux contribution at
(ii) From the usual diagnostic-diagrams, we observed that
almost all galaxies have emission line-ratios typical of H II region
spectra. However, we noticed that many of these line-ratios are found
very close to the transition zone between H II regions and LINERs. In
fact, the (iii) We investigated the possible nature of the galaxies with line ratios in the transition zone between H II regions and AGN assuming that these objects could have a composite spectrum due to the simultaneous presence on the slit of a Seyfert nucleus and an H II region. To test this hypothesis we built composite spectra contaminating emission-pure AGN spectra with H II regions of solar abundance. We found that this model applies to 15 objects (and possibly 5 others) in our sample, indicating that they might host a low-luminosity AGN . The true nature (LINER or type 1 and 2 Seyfert) of the AGN can only be revealed through high spatial resolution spectroscopy. It is interesting to point out that both components of the pairs AM 1118-350, AM 1304-333, AM 2229-735 and AM 2322-821 possibly host a low-luminosity active nucleus. ![]() ![]() ![]() ![]() © European Southern Observatory (ESO) 1999 Online publication: June 18, 1999 ![]() |