Aims. This work exhibits the basic optical photometric data for a sample of 50 probable southern binary galaxies. Our sample covers a broad range of pair separations, stages of interaction, and morphologies. From the initial list of selected pairs, using spectroscopic data from the literature and our own data, we conclude that 84% of these systems are true binary galaxies. Methods. We present residual and asymmetric maps, R major semi-axis profiles of surface brightness, ellipticity, position-angle, harmonic Fourier coefficients of third and fourth order (b 3 and b 4 ) for 50 probable pairs, and B − R color maps for 47 of these pairs. For most galaxies, we present the profiles in two different ways, aiming to verify the influence of random errors on them. Results. We note that random errors in position-angle profiles are at least 2• , but a more significant result must take into account a variation larger than 11• for this distribution. Barred galaxies usually show a typical behavior in ellipticity and position-angle profiles: these profiles display variations when changing from a bar to a disk region. In some cases, the variations also occur along the bar. Some galaxies show distribution profiles that are common for their morphological type, and the interaction signature is only evidenced by their residual maps. Bars are usually redder and rings are bluer, when compared with the galaxy outskirts. Conclusions. Our data indicates that there is a connection between interaction strength and morphological distortions in binary galaxies. If we consider the projected separation of a pair as an indication of interaction strength, distortions such as displaced centers, anomalous shapes of spiral arms, and twistings of external regions are easily detected in some close pairs, although not all components of close pairs show this behavior. Our data suggests that besides interaction, other parameters, like orbital geometry and internal properties of galaxies, can stimulate binary galaxies' peculiarities.

Aims. This work is part of a joint observational program aiming to get photometric and spectroscopic information on southern pairs of galaxies. We present optical long-slit spectroscopic data on 80 probable components of pairs, 61 of them collected with a spectral resolution of 3.4 Å, and 19 with 12 Å. Nevertheless, our analysis takes into account 53 components of pairs with better spectral resolution, as 8 of these target galaxies actually belong to optical pairs. For the sample with better resolution, the covered wavelength range is 5724 ≤ λ ≤ 7036 Å. The spectroscopic and photometric information is gathered for an analysis relating galaxy morphologies to their spectra. Methods. We use H α + [N II ] and H α equivalent widths as star formation tracers for the central region of our sample galaxies, and we classify the spectra according to the emission lines' relative strength by looking at their behavior. Results. Some of our sample galaxies exhibit high central star formation, most of them belonging to close pairs. However, not all galaxies' components of close pairs show this behavior. This may be a clue that besides interaction, other agents can stimulate central emission in binary galaxies. We suggest an enhancement in the number of galaxies with peculiar spectra (probably Seyferts) in our binary sample, when compared to isolated galaxies. Our data indicates that the morphological types of interacting galaxies are related to their spectral characteristics, as almost all early-type galaxies of our sample do not exhibit central optical emission. We note that the star formation activity is most likely to take place in both pairs' components, with a slightly higher mean strength for the less bright component of the pair. It is interesting to point out that most spirals exhibiting a strong HII emission line spectra present either a bar or a peculiarity, but on a general basis we do not find an enhancement of star formation in our interaction sample.