WFI Exoplanet Microlensing Light Curve Generator and Fitter

Summary

For the last few years, the software package called MulensModel was developed to make it easy to join microlensing research. The package provides a framework for calculating microlensing model magnification curves and goodness-of-fit statistics for microlensing events with single and binary lenses as well as a variety of higher-order effects: extended sources with limb-darkening, microlensing parallax (annual or satellite), binary sources, binary lens orbital motion, shear, convergence, and almost any combination of them. The software is easily adaptable to analyze the planned microlensing survey with the Roman Space Telescope.

Generating the Microlensing Models and Comparing to Photometric Data

MulensModel produces light curves and compares them to models. It uses three Python types: Model, Mulensdata and Event. A set of parameters stored in the ModelParameters class specifies Model. The photometric dataset (epochs, photometric measurements, and their uncertainties) are stored in MulensData. Finally, the Event class combines the MulensData instances with an instance of Model. The main method used is to calculate the χ² statistic. The magnification is calculated, and the flux from surrounding stars in a crowded region is taken into account. The annual microlensing parallax and the satellite microlensing parallax may be taken into account here as well. The lenses can be single lenses or binary lenses. There are examples that show how to use the code, and one of them allows fitting a wide variety of models using different fitting methods and producing different output files, with convenient control from a single input file.

MulensModel Microlensing Model Fitter

MulensModel is available at https://github.com/rpolenski/MulensModel/ together with current documentation and examples. The earlier version of the code was described in detail by Poleski & Yee (2018).