Fishman et al., 1994; Ryan et al., 1994). It means that up to now it is sufficiently reasonable to suppose that the source of these mysterious events is a “compact object” with probable strong (not damped) magnetic field.

Further we assume that potential sources of [$\gamma$]{}–ray bursts can be among objects forming the hidden mass of the Galaxy. For the vicinity of the Sun, which we are basically interested here in, the upper limit to the contribution of unknown objects to the total density of matter (or Oort’s limit deduced from observed star velocities along $z$ coordinate) is determined and is approximately 38% (Lacarrieu, 1971). Thus, we assume that the objects sought may be rather old, in particular, their velocities can be close to the velocities of the oldest pulsars. And the total expected number of such objects in the optical and in the soft X–rays is bounded above by the density of hidden mass, which gives the local (in the vicinity of the Sun) numerical density of compact objects with the mass of $\rm
1.4\,M_{\sun}$ equal to $0.0357\,\rm  pc^{-3}$.

The total number of such objects can be bounded below by the number of all neutron stars, which could be 