pyLIMA: An Open-source Package for Microlensing Modeling. I. Presentation of the Software and Analysis of Single-lens Models

Abstract

Microlensing is a unique tool, capable of detecting the "cold" planets between ∼1-10AU from their host stars, and even unbound "free-floating" planets. This regime has been poorly sampled to date owing to the limitations of alternative planet-finding methods, but a watershed in discoveries is anticipated in the near future thanks to the planned microlensing surveys of WFIRST-AFTA and Euclid's Extended Mission. Of the many challenges inherent in these missions, the modeling of microlensing events will be of primary importance, yet is often time consuming, complex and perceived as a daunting barrier to participation in the field. The large scale of future survey data products will require thorough but efficient modeling software, but unlike other areas of exoplanet research, microlensing currently lacks a publicly-available, well-documented package to conduct this type of analysis. We present first version 1.0 of pyLIMA: Python Lightcurve Identification and Microlensing Analysis 1 . This software is written in Python and uses existing packages as much as possible, to make it widely accessible. In this paper, we describe the overall architecture of the software and the core modules for modeling single-lens events. To verify the performance of this software, we use it to model both real datasets from events published in the literature and generated test data, produced using pyLIMA's simulation module. Results demonstrate that pyLIMA is an efficient tool for microlensing modeling. We will expand pyLIMA to consider more complex phenomena in the following papers.

Models and Simulations for the Photometric LSST Astronomical Time Series Classification Challenge (PLAsTiCC)

“…PyLIMA: This method is based on the first opensource microlensing software tool 25 (Bachelet et al 2017). We compute u(t) (Eq.…”

VVV Survey Microlensing: Catalog of Best and Forsaken Events

“…The microlensing surveys in general are not designed to find binary events because of their wide variety of light curve shapes. Anyway, there are new tools to deal with such events like PyLima (Bachelet et al 2017) specially designed for the detection of extrasolar planets with the WFIRST. Binary events contain additional information (relative proper motions) that potentially allows to break the degeneracy between masses and distances.…”

Confirmation of the Stellar Binary Microlensing Event, Macho 97-BLG-28

“…We use the Python microlensing modelling package pyLIMA to model the event light curve. pyLIMA is the first open-source package designed specifically for microlensing (Bachelet et al 2017), and is available on the Github platform 1 . In the first instance we perform two fits, MOD1 and MOD2, the results of which are shown in Table 2.2.…”

“…We refit the light curve of MACHO-97-BLG-28 using the original data set with these modifications. We model the event using the open-source microlensing modelling package, pyLIMA (Bachelet et al 2017), both with and without additional unpublished data from the Mt. Stromlo (MSO) 74" telescope.…”