Galactic globular clusters contribution to microlensing events?

TL;DR

This paper investigates whether some microlensing events toward the Galactic center are caused by lenses within globular clusters, suggesting possible dark matter candidates like brown dwarfs or stellar remnants.

Contribution

It provides the first analysis linking specific microlensing events to globular cluster lenses and estimates the nature of these deflectors.

Findings

Four microlensing events may be due to globular cluster lenses

Estimated lens masses suggest brown dwarfs, M-stars, or stellar remnants

Some events are highly aligned with globular cluster centers

Abstract

In this note we perform an analysis of the large set of microlensing events detected so far toward the Galactic center with the purpose of investigating whether some of the dark lenses are located in Galactic globular clusters. We find that in four cases some events might indeed be due to lenses located in the globular clusters themselves. We also give a rough estimate for the average lens mass of the subset of events being highly aligned with Galactic globular cluster centers and find that, under reasonable assumptions, the deflectors could most probably be either brown dwarfs, M-stars or stellar remnants.