Trajectories of the images in binary microlensing

Abstract

We study in detail the trajectories followed by single images during binary microlensing events. Starting from perturbative resolutions of the lens equation, we explore the full parameter space by continuity arguments. We see that the images created during the caustic crossing can recombine with the others in different ways. This leads to a new classification of the microlensing events according to the behaviour of the images. We show that the images involved in these combinations depend on the folds that are crossed at the entry and at the exit from the caustic. Non-trivial trajectories can be classified into four main types. Some consequences for the motion of the center of light of the source in astrometric measurements are also examined.

15 pages, 8 figures, in press on Astronomy & Astrophysics

References in corpus (5)

• A Complete Set of Solutions For Caustic-Crossing Binary Microlensing Events
• Astrometric Properties of Gravitational Binary-Microlens Events and Their Applications
• Astrometric Microlensing as a Method of Discovering and Characterizing Extra-Solar Planets
• Astrometric Resolution of Severely Degenerate Binary Microlensing Events
• Signs of the cusps in binary lenses

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• Extended Source Diffraction Effects Near Gravitational Lens Fold Caustics
• Never bet against Einstein
• The Importance of Binary Gravitational Microlensing Events Through High-Magnification Channel
• Gaia20fnr: A binary-lens microlensing event with full orbital motion revealed by four space telescopes