Robert M. Walker Distinguished Lecture Series Colloqiuium
Astrophysicists have discovered two populations of black holes in the universe: stellar-mass black holes with masses in the range of 5 to 20 solar masses, and supermassive black holes with masses in the range of a million to several billion solar masses. According to the general theory of relativity, each black hole is completely described with just two parameters: its mass and its spin. Measuring these two parameters for individual black holes and relating the measured values to specific observational manifestations of the holes is a major area of research. The talk will describe some recent progress in the field.