Search for heavy blackholes with Microlensing: The MEMO project

TL;DR

This paper explores combining long-term microlensing data from multiple surveys to detect very heavy black holes in the Milky Way halo, potentially revealing their contribution to dark matter.

Contribution

It proposes a systematic combined analysis of existing microlensing data to identify heavy black holes, which individual surveys might miss.

Findings

Potential to detect ~10 black hole microlensing events of 100 million solar masses.

Combined analysis could quantify the black hole component in the Galactic halo.

Demonstrates feasibility of overcoming passband differences for joint data analysis.

Abstract

The historical microlensing surveys MACHO, EROS, MOA and OGLE (hereafter summarized in the MEMO acronym) have searched for microlensing toward the LMC for a total duration of 27 years. We have studied the potential of joining all databases to search for very heavy objects producing several year duration events. We show that a combined systematic search for microlensing should detect of the order of 10 events due to $100M_\odot$ black holes, that were not detectable by the individual surveys, if these objects have a major contribution to the Milky-Way halo. Assuming that a common analysis is feasible, i.e. that the difficulties due to the use of different passbands can be overcome, we show that the sensitivity of such an analysis should allow one to quantify the Galactic black hole component.