Lens Masses and Distances from Microlens Parallax and Flux

Abstract

I present a novel method for measuring lens masses for microlensing events. By combining a measured lens flux with the microlens parallax vector pi_E, it is possible to derive the mass of the lens system without knowing the angular size of the Einstein ring, theta_E. This enables mass and distance measurements for single, luminous lenses, as well as binary and planetary lenses without caustic crossings. I discuss applications of this method in the contexts of the Spitzer, Kepler, and WFIRST microlensing missions.Comment: 9 pages, 2 figures, submitted to ApJ Letters; minor corrections made in response to comments from the communit