Rigorous "Rich Argument" in Microlensing Parallax

Andrew Gould

I show that when the observables $({\vec{\pi }}_{\mathrm{E}},t_{\mathrm{E}},{\theta }_{\mathrm{E}},{\pi }_s,{\vec{\mu }}_s)$ are well measured up to a discrete degeneracy in the microlensing parallax vector $\vec π_{\rm…