Measuring the microlensing parallax from various space observatories

TL;DR

This paper reviews methods for measuring microlensing parallax using space observatories, including lunar-based telescopes, and discusses the advantages and limitations of these approaches for determining lens mass and distance.

Contribution

It generalizes Fisher matrix analysis for various space-based microlensing parallax measurement scenarios, highlighting the potential and challenges of lunar-based observations.

Findings

Lunar-based parallax observations face significant parameter correlation issues.

Fisher matrix analysis shows advantages of space observatories for parallax measurement.

Practical data modeling limits the detection efficiency of lunar parallax effects.

Abstract

A few observational methods allow the measurement of the mass and distance of the lens-star for a microlensing event. A first estimate can be obtained by measuring the microlensing parallax effect produced by either the motion of the Earth (annual parallax) or the contemporaneous observation of the lensing event from two (or more) observatories (space or terrestrial parallax) sufficiently separated from each other. Further developing ideas originally outlined by Gould (2013) and Mogavero & Beaulieu (2016), we review the possibility of measuring systematically the microlensing parallax using a telescope based on the Moon surface and other space-based observing platforms including the upcoming WFIRST space-telescope. We first generalize the Fisher matrix formulation and present results demonstrating the advantage for each observing scenario. We conclude by outlining the limitation of the Fisher matrix analysis when submitted to a practical data modeling process. By considering a lunar-based parallax observation we find that parameter correlations introduce a significant loss in detection efficiency of the probed lunar parallax effect.