A public code for astrometric microlensing with contour integration

TL;DR

This paper introduces the first publicly available code for calculating astrometric centroid shifts in microlensing events, enabling detailed analysis of finite source effects in binary systems.

Contribution

It provides a novel, publicly accessible contour integration-based tool for precise astrometric microlensing calculations involving finite sources and limb darkening.

Findings

First public code for astrometric microlensing calculations

Supports single and binary lensing with arbitrary limb darkening

Enhances analysis capabilities for current and future surveys

Abstract

We present the first public code for the calculation of the astrometric centroid shift occurring during microlensing events. The computation is based on the contour integration scheme and covers single and binary lensing of finite sources with arbitrary limb darkening profiles. This allows for general detailed investigations of the impact of finite source size in astrometric binary microlensing. The new code is embedded in version 3.0 of VBBinaryLensing, which offers a powerful computational tool for extensive studies of microlensing data from current surveys and future space missions.