THE STABILITY OF UNIFORMLY ROTATING STELLAR DISKS

We explore a series expansion method to calculate the modes of oscilla tions for a variety of uniformly rotating finite disks, either with or without a dark halo. Since all models have the same potential, this s urvey focuses on the role of the distribution function in stability an alyses. We show that the stability behaviour is greatly influenced by the structure of the unperturbed distribution, particularly by its ene rgy dependence. In addition we find that uniformly rotating disks with a halo in general can feature spiral-like instabilities.