Searching for stars in compact high-velocity clouds - II

We address the hypothesis that high-velocity clouds correspond to the 'missing' dwarf galaxies of the Local Group predicted by cosmological simulations. To this end, we present optical and near-infrared photometry of five additional high-velocity clouds, one of which produces Lyman series absorption on the sight line towards the quasar Ton S210, with sufficient resolution and sensitivity to enable the detection of an associated stellar content. We do not detect significant stellar populations intrinsic to any of the five clouds. In combination with the results from our Paper I, which had yielded non-detections of stellar content in another five cases, we find that there is a 50 per cent chance of getting a null result in 10 trials if fewer than 7 per cent of all high-velocity clouds contain stars. We conclude that the population of high-velocity clouds is an unlikely repository for the 'missing' dwarfs of the Local Group.