2006ApJ...637..752K

The observed spectra of the microlensed sources toward the Galactic bulge may be used as a tool for studying the kinematics and extinction effects in the Galactic bulge. In this paper, we first investigate the expected distribution of the microlensed sources as a function of depth within the Galactic bulge. Our analysis takes a magnitude-limited microlensing survey into account and includes the effects of extinction. We show that in the current magnitude-limited surveys, the probability that the source lies at the far side of the bulge is larger than the probability that the source lies at the near side. We then investigate the effects of extinction on the observed spectra of microlensed sources. Kurucz model spectra and the observed extinctions toward the Galactic bulge have been used to demonstrate that the microlensed sources should clearly show the effects of extinction, which, in turn, can be used as a statistical measure of the contribution of the disk lenses and bulge lenses at different depths. The spectra of the microlensed sources provide a unique probe to derive the radial velocities of a sample that lies preferentially at the far side of the Galactic bulge. The radial velocities, coupled with the microlensing timescales, can thus be useful in studying the three-dimensional kinematics of the Galactic bulge.