[$\gamma$]{}–ray boxes were studied at this level of signal detection in ROSAT ASS (Boer et al., 1993a)). If based on this flux value, then at $T_{bb}  > 200000\rm~ K$, even for a spatial density (lower estimate) of $0.001 \rm~ pc^{-3}$ in ROSAT ASS, there must be a considerable number (about 30 sources up to 20 pc) of bright ($\sim4\cdot10^{-12}\,{\rm  erg\cdot
cm^{-2}\cdot s^{-1}}$) X–ray sources, which could be identified long ago if they existed indeed. So far there are no unidentified [*bright*]{} X-ray sources (J.Greiner, private communication), and from the absence of large number of coincidences of weak X–ray sources with small [$\gamma$]{}–ray boxes (Greiner et al., 1995) it should be expected that even if such objects do exist in Nature, then their temperature is lower than $1-2\cdot10^{5}$K, according to Fig.1.

At $T_{bb} \la 10^{5}\, \rm K$ even at a maximum allowable density of such objects in the vicinity of the Sun ($0.0357\, \rm~ pc^{-3}$) in ROSAT ASS a very small number should be expected of corresponding X–ray sources with a typical flux of $\ga 5\cdot10^{-13}\, {\rm   erg\cdot
cm^{-2}\cdot s^{-1}}$. At the same time, as is seen from Fig.1, corresponding compact objects with temperatures from 50000 K to 150000 K will 