Thermal equilibrium of an ideal gas in a free-floating box

Abstract

The equilibrium and fluctuations of an ideal gas in a rigid container are studied by every student of statistical mechanics. Here we study the less well-known case when the box is floating freely; in particular we determine the fluctuations of the box in velocity and position due to interactions with the gas it contains. This system is a toy model for the fluctuations in velocity and position of a black hole surrounded by stars at the center of a galaxy. These fluctuations may be observable in nearby galaxies.

5 pages, no figures, submitted to American Journal of Physics

References in corpus (4)

• The Proper Motion of Sagittarius A*: III. The Case for a Supermassive Black Hole
• A Displaced Supermassive Black Hole in M87
• Henize 2-10: the ongoing formation of a nuclear star cluster around a massive black hole
• Gravitational Brownian motion as inhomogeneous diffusion: black hole populations in globular clusters