Rogue worlds meet the dark side: revealing terrestrial-mass primordial black holes with the Nancy Grace Roman Space Telescope

Understand

Gravitational microlensing is one of the strongest observational techniques to observe non-luminous astrophysical bodies.

• Existing microlensing observations provide tantalizing evidence of a population of low-mass objects whose origin is unknown.
• These events may be caused by terrestrial-mass free-floating planets or by exotic objects such as primordial black holes.
• However, the nature of these objects cannot be resolved on an event-by-event basis, as the induced light curve is degenerate for lensing bodies of identical mass.