Estimating Finite Source Effects in Microlensing Events due to Free-Floating Planets with the Euclid Survey

Abstract EN

In recent years free-floating planets (FFPs) have drawn a great interest among astrophysicists.

Gravitational microlensing is a unique and exclusive method for their investigation which may allow obtaining precious information about their mass and spatial distribution.

The planned Euclid space-based observatory will be able to detect a substantial number of microlensing events caused by FFPs towards the Galactic bulge.

Making use of a synthetic population algorithm, we investigate the possibility of detecting finite source effects in simulated microlensing events due to FFPs.

We find a significant efficiency for finite source effect detection that turns out to be between 20% and 40% for a FFP power law mass function index in the range [0.9, 1.6].

For many of such events it will also be possible to measure the angular Einstein radius and therefore constrain the lens physical parameters.

These kinds of observations will also offer a unique possibility to investigate the photosphere and atmosphere of Galactic bulge stars.