Astrometric Properties of Gravitational Binary-Microlens Events and Their Applications

Abstract

In this paper, we study the astrometric properties of gravitational microlensing events caused by binary lenses. By investigating the centroid shifts for various types of binary-lens events, we find that the deviations of the centroid shift trajectories from the elliptical ones of single-lens events are characterized by distortions, twistings, and big jumps. We study the conditions of binary-lens system configurations and source star trajectories for individual types of deviations. We find dramatic differences in the astrometric centroid shifts for binary-lens microlensing events that would be degenerate had their parameters been determined photometrically. Therefore, when additional astrometric observations of a binary-lens event are available, one can resolve the ambiguity of the binary-lens fit, and uniquely determine the binary-lens parameters.

total 15 pages, including 5 Figures and no Table, submitted to ApJ

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Cited by in corpus (20)

• Microlens Masses From Astrometry and Parallax in Space-Based Surveys: From Planets to Black Holes
• Microlensing Searches for Exoplanets
• Astrometric Microlensing of Quasars : Dependence on surface mass density and external shear
• Gravitational Microlensing Near Caustics I: Folds
• Applications of Microlensing to Stellar Astrophysics
• Orbital motion effects in astrometric microlensing
• Prediction of Astrometric Microlensing Events during the Gaia Mission
• Effect of a wide binary companion to the lens on the astrometric behavior of gravitational microlensing events
• Astrometric Resolution of Severely Degenerate Binary Microlensing Events
• A public code for astrometric microlensing with contour integration
• Microlensing Binaries Discovered through High-Magnification Channel
• Trajectories of the images in binary microlensing
• Astrometric microlensing
• Parallax and orbital effects in astrometric microlensing with binary sources
• Influence of the Galactic gravitational field on the positional accuracy of extragalactic sources
• Never bet against Einstein
• The Importance of Binary Gravitational Microlensing Events Through High-Magnification Channel
• A New Application of the Astrometric Method to Break Severe Degeneracies in Binary Microlensing Events
• Detecting binarity of GW150914-like lenses in gravitational microlensing events
• Angular Radii of Stars via Microlensing