We report the extremely high magnification ( A > 1000 ) binary microlensing event OGLE-2007-BLG-514 .
We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories .
The binary lens model that includes the effects of parallax ( known orbital motion of the Earth ) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 \pm 0.007 and a projected separation of s = 0.072 \pm 0.001 in units of the Einstein radius .
The parallax parameters allow us to determine the lens distance D _ { L } = 3.11 \pm 0.39 kpc and total mass M _ { L } = 1.40 \pm 0.18 M _ { \odot } ; this leads to the primary and secondary components having masses of M _ { 1 } = 1.06 \pm 0.13 M _ { \odot } and M _ { 2 } = 0.34 \pm 0.04 M _ { \odot } , respectively .
The parallax model indicates that the binary lens system is likely constructed by the main sequence stars .
On the other hand , we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap ( possible orbital motion of the source around a companion ) and parallax ( q = 0.270 \pm 0.005 , s = 0.083 \pm 0.001 ) .
The primary component of the binary lens is relatively massive with M _ { 1 } = 0.9 _ { -0.3 } ^ { +4.6 } M _ { \odot } and it is at a distance of D _ { L } = 2.6 _ { -0.9 } ^ { +3.8 } kpc .
Given the secure mass ratio measurement , the companion mass is therefore M _ { 2 } = 0.2 _ { -0.1 } ^ { +1.2 } M _ { \odot } .
The xallarap model implies that the primary lens is likely a stellar remnant , such as a white dwarf , a neutron star or a black hole .