| Description |
All stars with initial masses of larger than 20 solar mass are expected to end their lives as black holes. Yet, not a single isolated black hole has been detected in the Galaxy. Astrometric microlensing is the only available technique capable of detecting isolated black holes and measuring their masses. I will discuss the technique of astrometric microlensing, and two HST programs underway aimed at the first detections of isolated, stellar-mass black holes through this technique. |