Stability of spherical stellar systems -- I. Analytical results

Stability of rotating spherical stellar systems

We study the stability of rotating collisionless self-gravitating spherical systems by using high resolution N-body experiments on a Connection Machine CM-5. We added rotation to Ossipkov-Merritt (hereafter OM) anisotropic spherical systems by using two methods. The first method conserves the anisotropy of the distribution function defined in the OM algorithm. The second method distorts the sys...

Cusped Spherical Stellar Systems with Anisotropic Velocities

Spherical models with constant velocity anisotropy β have distribution functions depending on binding energy E and angular momentum L of the form f (E, L) = L−2β fE(E). An inversion for the unknown function fE (E) is straightforward to derive and reduces to Eddington’s famous algorithm for isotropic models (β = 0). Importantly, if the anisotropy parameter of the model is a half-integer constant...

Stability results for set solution of fuzzy integro-differential systems

The Spherical Symmetry of Static Stellar Systems in General Relativity

Abstract. A conjecture of many years standing in General Relativity is that static stellar models, under physically reasonable assumptions, must be spherically symmetric. Despite some real progress in the last eighteen years (Beig and Simon, Masood-ul-Alam) a proof of the conjecture, in its full generality, has remained elusive. We consider asymptotically flat, perfect fluid, static stellar spa...

Perturbations of spherical stellar systems during flyby encounters

We study the internal response of a galaxy to an unbound encounter and present a survey of orbital parameters covering typical encounters in different galactic environments. Overall, we conclude that relatively weak encounters by low-mass interloping galaxies can cause observable distortions in the primaries. The resulting asymmetries may persist long after the interloper is evident. We focus o...