Abstract Details
| Name: Chanda J. Jog Affiliation: Indian Institute of Science, Bangalore Conference ID: ASI2015_994 Title : Gravitational instabilities affected by external tidal field Abstract Type : Plenary Abstract : The well-known Jeans criterion describes the onset of instabilities in an infinite, homogeneous, self-gravitating medium supported by pressure. Most realistic astrophysical systems, however, are not isolated. A modified instability criterion for a system in an external tidal field has been obtained. A typical, disruptive field is shown to make the system more stable against perturbations resulting in a higher effective Jeans mass. Conversely, a compressive tidal field, as seen in centres of galaxies, makes it easier to form instabilities. Similarly, the Toomre Q criterion for a rotating disk gets modified, and the external dark matter halo is shown to stabilize a galactic disk. This can help explain why star formation is suppressed in Low-Surface-Brightness galaxies which are dominated by dark matter halo at all radii. |