SIMBAD references

Using ground-based UBVRIHα CCD photometry we have been carrying out a search for young massive star clusters (YMCs) in a sample consisting of 21 nearby spiral galaxies. We find a large variety concerning the richness of the cluster systems, with some galaxies containing no YMCs at all and others hosting very large numbers of YMCs. Examples of galaxies with poor cluster systems are NGC 300 and NGC 4395, while the richest cluster systems are found in the galaxies NGC 5236 (M 83), NGC 2997 and NGC 1313. The age distributions of clusters in these galaxies show no obvious peaks, indicating that massive clusters are formed as an ongoing process rather than in bursts. This is in contrast to what is observed in starbursts and merger galaxies. The radial distributions of clusters follow the Hα surface brightnesses. For the galaxies in our sample there is no correlation between the morphological type and the presence of YMCs.