Astrometric Resolution of Severely Degenerate Binary Microlensing Events
arXiv:astro-ph/0001193 · doi:10.1086/309180
Abstract
We investigate whether the "close/wide" class of degeneracies in caustic-crossing binary microlensing events can be broken astrometrically. Dominik showed that these degeneracies are particularly severe because they arise from a degeneracy in the lens equation itself rather than a mere "accidental" mimicking of one light curve by another. A massive observing campaign of five microlensing collaborations was unable to break this degeneracy photometrically in the case of the binary lensing event MACHO 98-SMC-1. We show that this degeneracy indeed causes the image centroids of the wide and close solutions to follow an extremely similar pattern of motion during the time when the source is in or near the caustic. Nevertheless, the two image centroids are displaced from one another and this displacement is detectable by observing the event at late times. Photometric degeneracies therefore can be resolved astrometrically, even for these most severe cases.
11 pages, including 4 figures. Submitted to ApJ
References in corpus (10)
- Detection of Rotation in a Binary Microlens: PLANET Photometry of MACHO 97-BLG-41
- Predicting Stellar Angular Sizes
- Combined Analysis of the Binary-Lens Caustic-Crossing Event MACHO 98-SMC-1
- Limb-Darkening of a K Giant in the Galactic Bulge: PLANET Photometry of MACHO 97-BLG-28
- Observations of the Binary Microlens Event MACHO-98-SMC-1 by the Microlensing Planet Search Collaboration
- A Complete Set of Solutions For Caustic-Crossing Binary Microlensing Events
- Detection Efficiencies of Microlensing Datasets to Stellar and Planetary Companions
- Spectrophotometric Resolution of Stellar Atmospheres with Microlensing
- Discovery and Characterization of a Caustic Crossing Microlensing Event in the SMC
- Astrometric Properties of Gravitational Binary-Microlens Events and Their Applications
Cited by in corpus (16)
- Microlens Masses From Astrometry and Parallax in Space-Based Surveys: From Planets to Black Holes
- Full characterization of binary-lens event OGLE-2002-BLG-069 from PLANET observations
- Astrometric Microlensing of Quasars : Dependence on surface mass density and external shear
- Gravitational Microlensing Near Caustics I: Folds
- Orbital motion effects in astrometric microlensing
- Applications of Microlensing to Stellar Astrophysics
- Photometric, Astrometric and Polarimetric observations of gravitational microlensing events
- A Short, Non-Planetary, Microlensing Anomaly: Observations and Lightcurve Analysis of MACHO 99-BLG-47
- Microlens Parallaxes of Binary Lenses Measured from a Satellite
- Microlensing Binaries Discovered through High-Magnification Channel
- Trajectories of the images in binary microlensing
- Numerically studying the degeneracy problem in extreme finite-source microlensing events
- Microlensing by gas filaments
- MAGIC: Microlensing Analysis Guided by Intelligent Computation
- A New Application of the Astrometric Method to Break Severe Degeneracies in Binary Microlensing Events
- Angular Radii of Stars via Microlensing