Jeans equations, velocity dispersion, and fluid dynamics
Today’s reading was more challenging than usual because of the “tricks” involved in the derivations as well as the usage of fluid equations. It appears that if I want to fully understand the rest of the Galactic Dynamics text, I will have to review and learn more fluid dynamics. I’ve been wanting to learn more fluid dynamics theory and now I have a reason. Every good physicist should know fluid dynamics.
I went through the derivation of Jeans equations, the velocity dispersion tensor, and the tensor form of the Virial theorem for collisionless systems. I now have a much better understanding of why velocity dispersion is a useful thing to measure.