Chatterjee, PinakiHernquist, LarsLoeb, Abraham2019-09-202002Chatterjee, Pinaki, Lars Hernquist, and Abraham Loeb. 2002. “Brownian Motion in Gravitationally Interacting Systems.” Physical Review Letters 88 (12). https://doi.org/10.1103/physrevlett.88.121103.0031-90071079-71141092-0145http://nrs.harvard.edu/urn-3:HUL.InstRepos:41381791wWe derive a model that describes the dynamics of a Brownian particle, such as a massive black hole, in a stellar system dominated by gravitational forces, and examine whether it achieves a state of equipartition of kinetic energy with the stars. This problem has been considered before only for stellar systems with an isothermal Maxwellian distribution of velocities; here we study other examples and confirm our calculations with N-body simulations. We show that in certain cases the black hole's steady state kinetic energy can be very far from equipartition.en-USJournal Article2019-09-2010.1103/PhysRevLett.88.121103