1 / 36

Understanding Collisionless Dynamics V: Virial Theorems & Applications in Gravitating Systems

Explore the tensor and scalar virial theorems to analyze structural and kinematic properties in collisionless dynamics, with applications in determining mass-to-light ratios, spheroid flattening, and dynamical friction effects. Discover the role of relaxation mechanisms and chaotic mixing in gravitational systems, shedding light on phenomena like violent relaxation and NFW-like profiles.

nelle-farley
Télécharger la présentation

Understanding Collisionless Dynamics V: Virial Theorems & Applications in Gravitating Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Collisionless Dynamics V:Relaxation and Equilibrium

  2. Review • Tensor virial theorem relates structural properties (d2Iij/dt2) to kinematic properties (random KE + ordered KE + potential E). • Scalar virial theorem: 2K + W [+ SP] = 0. • Applications: • Mvir from half-light radius and velocity dispersion. • M/L from S, s (assuming spherical, non-rot) • Flattening of spheroids v/s. • Jeans theorem: Can express any DF as fcn of integrals of motion (E, Lz, L, I3, …).

  3. Summary • Relaxation is driven by phase mixing and chaotic mixing, with violent relaxation being dominant in collisionless mergers. • The end state of merging appears to be not fully relaxed; the origin of NFW-like profiles still not fully understood. • Dynamical friction (braking due to wakes) can cause orbital decay in several orbital times. • Heat capacity of gravitating systems is negative, hence cuspy systems with short relaxation time undergo gravothermal collapse (e.g. globulars).

More Related