Institute for Advanced Study Informal Astrophysics Seminar - NOTE TIME CHANGE

A massive black hole resides in the center of most, perhaps all galaxies. The one in the center of our home galaxy, the Milky Way, provides a uniquely accessible laboratory for studying in detail the connections and interactions between a massive black hole and the stars in its vicinity. Due to the the extreme conditions in this region (highest stellar densities, velocities and tidal fields) unique processes can occur there. These processes and their implication on the stellar population near the massive black hole open new possibilities in our understanding of gravitational dynamics and of post-Newtonian gravity in the weak- and strong-field limits. They may also explain and predict the existence of stars with exotic properties. In recent years young stars have been observed at the center of our Galaxy where such stars can not regularly form. At the outskirts of the Galaxy hypervelocity stars have been observed to escape from the Galaxy at extreme velocities. I will discuss the origin and evolution of these two unique population of stars and the possible connection between them, through the dynamical processes occurring near the massive black hole in the Galactic center. In addition I will discuss the possibility of using hypervelocity stars as probes of the Galactic potential; the production of gravitational wave sources both in the Galactic center and in other galactic nuclei [detectable by the planned Laser interferometer space antenna (LISA) mission]; and the possibility of directly probing the properties of the massive black hole in the Galactic center (its mass and its spin) and their general relativistic effects.