Historic microlensing events in the euclid Galactic Bulge Survey

TL;DR

This paper compiles and analyzes a comprehensive catalog of 8081 past microlensing events in the Euclid Galactic Bulge Survey, estimating their potential for lens-source resolution to guide future observations and studies.

Contribution

It provides the first complete catalog of past microlensing events in the Euclid survey area, with modeled proper motions and resolution probabilities to prioritize targets.

Findings

Catalog of 8081 microlensing events compiled and modeled.

Estimated resolution probabilities for each event to guide future observations.

Prioritized events, especially planetary microlensing cases, for successful lens-source separation.

Abstract

Microlensing campaigns have a long history of observations covering the Galactic bulge, where thousands of detections have been obtained, including many exoplanetary systems. The Euclid Galactic Bulge Survey represents a unique opportunity to revisit a large number of past events and attempt the lens-source resolution of known events falling in the covered area. As the analysis of individual events requires non-negligible efforts, it is important to establish priorities among all possible targets, identifying those candidates with the higher chance for a successful resolution of the lens from the source and with the highest scientific interest. Drawing from the databases of the three main microlensing surveys (OGLE, MOA and KMTNet), we compile the complete catalog of past microlensing events in the Euclid survey footprint up to year 2023, containing 8081 entries. By re-modeling all events and cross-checking with Galactic models, we estimate the relative lens-source proper motions for all events. Taking into account all uncertainties, for each microlensing event we are able to estimate the probability that the lens is separated from the source by more than a given angular distance threshold. Hence, we rank all events by their resolution probability, providing additional useful information that will guide future analyses on the most promising candidates. A particular attention is dedicated to known planetary microlensing events.