Microlensing and its Degeneracy Breakers: Parallax, Finite Source, High-resolution Imaging, and Astrometry

TL;DR

This paper reviews microlensing techniques, focusing on degeneracy-breaking methods like parallax, finite source effects, high-resolution imaging, and astrometry, to improve the understanding of compact objects and exoplanets.

Contribution

It provides a comprehensive overview of degeneracy breakers in microlensing, highlighting recent advances and future prospects for more accurate event characterization.

Findings

Astrometry helps resolve microlensing degeneracies.

High-resolution imaging improves event analysis.

Future observatories will enhance microlensing studies.

Abstract

First proposed by Paczynski in 1986, microlensing has been instrumental in the search of compact dark matter as well as discovery and characterization of exoplanets. In this article, we provide a brief history of microlensing, especially on the discoveries of compact objects and exoplanets. We then review the basics of microlensing and how astrometry can help break the degeneracy, providing a more robust determination of the nature of the microlensing events. We also outline prospects that will be made by on-going and forth-coming experiments/observatories