Galactic microlensing with rotating binaries

TL;DR

This paper investigates how rotating binary systems, including binary lenses, sources, and Earth's motion, affect galactic microlensing light curves, highlighting the importance of considering these effects for accurate modeling.

Contribution

It introduces a comprehensive analysis of rotating binary effects on microlensing light curves, including a case study with the DUO#2 event, and discusses when static models are sufficient.

Findings

Rotating binary lenses significantly alter caustic structures over time.

Including Earth's orbital motion improves microlensing event modeling.

A case study demonstrates the application of rotating binary lens fitting.

Abstract

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 motion of the earth 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.