Throughout this paper we have discussed the photometric and spectroscopic properties of a sample of galaxies selected from the Agüero Catalogue of Peculiar Galaxies.
From the analysis of the images we conclude that only 4 of
the selected objects are truly peculiar galaxies, namely:
NGC 3250E, ESO 
, NGC 3318 and ESO 
. The rest
of the sample consists in 5 normal spirals, ESO 
, NGC
3378, ESO 
, AM 
S, ESO 
, and one SO
galaxy, AM N.
A more detailed analysis of the images does not reveal signs
of mergers in the peculiar galaxies. Moreover, we could not
find companions for these galaxies in a 
field.
The luminosity profiles of normal and peculiar galaxies follow the r1/4 + exponential law except NGC 3250E. This galaxy shows a peculiar luminosity profile which clearly exhibits two exponential components, probably due to the presence of two different discs.
It is also observed that the luminosity profiles of normal and peculiar galaxies show features that are signatures of subsystems and star forming regions distributed throughout the galaxies. In this sense, it is interesting to observe that peculiar galaxies are indistinguishable, at least from a purely photometric point of view, from the normal ones. Most of the galaxies of the sample show from the B-V map several blue regions with (B-V) colors ranging from 0.2 to 0.6 indicating ongoing star formation. An interesting case is AM 2054-433 N which exhibits a V-I map that suggests star formation events in three different annulus concentric to the nucleus.
From the spectroscopic analysis we report a LINER-type
nucleus for the normal spiral ESO and a Seyfert 2
galaxy, AM 2054-433 N. We also confirm one LINER-type
spectrum for the spiral component of the interacting pair AM
2054-433. This fact was possible since we could subtract the
underlying stellar signatures using a database of early type
galaxy spectra. This technique proved to be a powerful tool
in order to search active galactic nuclei.
It is very suggesting that 3 of the 4 peculiar galaxies show
a starburst type spectrum. Moreover, the EW (H
+
[NII]) values measured in the integrated spectra of the
starburst galaxies indicate that these objects are under a
global burst of star formation which occurred 10 Myr ago.
For these galaxies we also find similar values EW (H
+ [NII]) 
60 Å, which is three times higher than
the observed average for the normal galaxies of the sample,
22 Å. We note that these starburst galaxies have
EW (H + [NII]) comparable to those in samples of
merging and interacting galaxies (L&K,
Donzelli &
Pastoriza 1997).
Although the origin of the mechanism that triggers star formation remains unclear, the analysis of these data suggests that the peculiar morphologies of these galaxies are closely related to global starbursts. However, due to the small size of our sample this idea is not conclusive. Further observations of peculiar galaxies are needed to support this hypothesis.
Acknowledgements
We are in debt with the staffs of CASLEO and UTSO for their excellent support. We acknowledge the very useful comments by the referee that greatly improved this paper. Many thanks to Dr. Diego Garcıa Lambas for the English revision. The authors acknowledge use of the CCD and data acquisition, system supported under U.S. National Science Foundation grant AST-90-15827, to R.M. Rich. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, CALTECH, under contract with the National Aeronautics and Space Administration.