## Galactic microlensing with rotating binaries
The influence of rotating binary systems on the light curves of galactic microlensing events is studied. Three different rotating binary systems are discussed: a rotating binary lens, a rotating binary source, and the earth's motion around the sun (parallax effect). The most dramatic effects arise from the motion of a binary lens because of the changes of the caustic structure with time. I discuss when the treatment of a microlensing event with a static binary model is appropriate. It is shown that additional constraints on the unknown physical quantities of the lens system arise from a fit with a rotating binary lens as well as from the earth-around-sun motion. For the DUO#2 event, a fit with a rotating binary lens is presented.
## Contents- 1. Introduction
- 2. Binary motion
- 3. Some basics of gravitational lensing
- 4. Rotating binary lenses
- 5. When is the rotation effect negligible?
- 6. Rotating binary sources
- 7. The parallax effect
- 7.1. Parameters
- 8. Additional constraints on the mass and other physical quantities
- 8.1. Using one constraint
- 8.1.1. From extended sources
- 8.1.2. From the observer's motion around the sun
- 8.1.3. From a rotating binary lens
- 8.2. Using two constraints
- 8.3. Using three constraints
- 8.1. Using one constraint
- 9. A fit with a rotating binary lens for DUO#2
- 10. Summary
- Appendix A: approximation of the trajectory to first order in
- References
© European Southern Observatory (ESO) 1998 Online publication: November 24, 1997 |