Gravitational lensing as a probe of compact object population in the   Galaxy
  The population of solitary compact objects in the Galaxy is very diffcult to investigate. In this paper we analyze the possibility of using microlensing searches to detect and to analyze the properties of the solitary black holes and neutron stars. Evolution of single and binary stars is considered using the StarTrack population synthesis code. We investigate the properties of the Galactic population of compact objects numerically. We find that the compact object lensing events are concentrated in a region with the radius of $\approx 5$ degrees around the Galactic center. The distribution of masses of the lenses for the models we consider differs but only slightly from the underlying massdistribution. The expected detection rates are of the order of a few per year. 
S. Oslowski, R. Moderski, T. Bulik, K. Belczynski