SIMBAD references

We present deep CCD photometry in B and R for a sample of bright unresolved objects around the compact group of interacting galaxies Hickson 90. Even though the maximum of the luminosity function is not reached in our data, there is a clear excess of objects having absolute B magnitude ~-9.0. The (B-R) colour index of these objects shows a marked excess of the blue objects, thus suggesting that they are recently formed populous clusters. The luminosity function of the clusters is the best fitted by a Gaussian with σ=1.4, which leads to a total cluster population of A=740±170. The large value of σ compared to the relatively small value of A, can be explained by some age dispersion among the young clusters. This result supports the hypothesis that strong interaction can trigger the formation of populous clusters.