Jeans instability of a galactic disk embedded in a live dark halo
Astronomisches Rechen-Institut am Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12–14, 69120 Heidelberg, Germany e-mail: email@example.com
Accepted: 3 April 2007
We investigate the Jeans instability of a galactic disk embedded in a dynamically responsive dark halo. It is shown that the disk-halo system becomes nominally Jeans unstable. On small scales the instability is suppressed, if the Toomre stability index QT is higher than a certain threshold, but on large scales the Jeans instability sets invariably in. However, using a simple self-consistent disk-halo model it is demonstrated that this occurs on scales which are much larger than the system so that this is indeed only a nominal effect. From a practical point of view the Jeans instability of galactic disks is not affected by a live dark halo.
Key words: galaxies: kinematics and dynamics / galaxies: halos
© ESO, 2007