SIMBAD references

We present optical imaging, spectroscopy and stellar population synthesis results for a sample of 4 mixed pairs of galaxies. The data allow us to estimate the degree of interaction with reasonable certainty. We conclude that one pair, AM1907-504, is likely to be an optical alignment. The remaining systems show radial velocity differences and morphology consistent with the hypothesis that they are physical binaries. Surface photometry allowed us to measure tidal distortions in the spiral components and to identify internal structure in the early-type members. We also made a stellar population synthesis study of the early-type components and find evidence for a young stellar population in the central regions of these galaxies. We consider possible origins for the young component as due either to mass-transfer from the spiral (cross-fuelling) or accretion events.