The complete catalogue of light curves in equal-mass binary microlensing

TL;DR

This paper provides the first comprehensive map of light curve morphologies in equal-mass binary microlensing, categorizing peaks and enabling optimized modeling of observed events.

Contribution

It introduces a complete parameter space map for equal-mass binary microlensing light curves, classifying all peak types and their regions.

Findings

73 distinct light curve morphologies identified

Parameter space partitioned into 232 regions

Enhanced modeling efficiency through initial condition selection

Abstract

The light curves observed in microlensing events due to binary lenses span an extremely wide variety of forms, characterised by U-shaped caustic crossings and/or additional smoother peaks. However, all peaks of the binary-lens light curve can be traced back to features of caustics of the lens system. Moreover, all peaks can be categorised as one of only four types (cusp-grazing, cusp-crossing, fold-crossing or fold-grazing). This enables us to present the first complete map of the parameter space of the equal-mass case by identifying regions in which light curves feature the same number and nature of peaks. We find that the total number of morphologies that can be obtained is 73 out of 232 different regions. The partition of the parameter space so-obtained provides a new key to optimise modelling of observed events through a clever choice of initial conditions for fitting algorithms.