What if dark matter is bosonic and self-interacting

Recently the problem of singular galactic cores and over-abundant formation of dwarf galaxies, inherent to the standard cold dal li matter model, had attracted a great deal of attention. One scenario which may be free of thes e problems invokes a self-interacting Dose-field. We find the limiting core density in this model due to the self-annihilation of the scaler field int o its own relativistic quanta. The limiting density may correspond to the o bservable one if there is only one dark matter component. Alternatively, th ere may be more than one dark matter species and the annihilation of one sp ecies may be very efficient with subsequent expansion of the: other, thus a voiding the problem of singular cores. (C) 2000 Elsevier Science B.V. All r ights reserved.