To account for the microlensing events observed in the Galactic halo , Gurevich , Zybin , and Sirota have proposed a model of gravitationally bound , noncompact objects with masses of \sim ( 0.01 \div 1 ) M _ { \odot } .
These objects are formed in the expanding Universe from adiabatic density perturbations and consist of weakly interacting particles of dark matter , for example , neutralinos .
They assumed the perturbation spectrum on some small scale to have a distinct peak .
We show that the existence of this peak would inevitably give rise to a large number of primordial black holes ( PBHs ) with masses of \sim 10 ^ { 5 } M _ { \odot } at the radiation-dominated evolutionary stage of the Universe .
Constraints on the coefficient of nonlinear contraction and on the compactness parameter of noncompact objects were derived from constraints on the PBH number density .
We show that noncompact objects can serve as gravitational lenses only at a large PBH formation threshold , \delta _ { \mathrm { c } } > 0.5 , or if noncompact objects are formed from entropic density perturbations .