2015ApJ...802..120D

We investigate properties of Galactic microlensing events in which a stellar object is lensed by a neutron star. For an all-sky photometric microlensing survey, we determine the number of lensing events caused by ∼ 10⁵ potentially observable radio pulsars to be ∼ 0.2/yr for 10¹⁰ background stellar sources. We expect a few detectable events per year for the same number of background sources from an astrometric microlensing survey. We show that such a study could lead to precise measurements of radio pulsar masses. For instance, if a pulsar distance could be constrained through radio observations, then its mass would be determined with a precision of ∼ 10%. We also investigate the timescale distributions for neutron star events, finding that they are much shorter than had been previously thought. For photometric events toward the Galactic center that last ∼15 days, around 7% will have a neutron star lens. This fraction drops rapidly for longer timescales. Away from the bulge region we find that neutron stars will contribute e 40% of the events that last less than ∼10 days. These results are in contrast to earlier work which found that the maximum fraction of neutron star events would occur on timescales of hundreds of days.