Tidal Torques and the Angular Momentum of Elliptcal Galaxies
Session 52 -- Elliptical Galaxies
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

## [52.14] Tidal Torques and the Angular Momentum of Elliptcal Galaxies

J.J. Gonz\'alez, S. Lizano, M. Osorio (IA-UNAM)

The behaviour of the angular momentum of a sample of elliptical galaxies is compared with theoretical predictions for tidal torques acting during the protogalactic phase as the source of galactic angular momentum (Heavens \& Peacock, 1988). The large range in the observed angular momenta at a fixed mass scale is consistent with the predicted dispersion in the spin parameter $\lambda \propto J M^{-5/3}$. There is a trend for less massive galaxies to have larger $\lambda$. This trend implies that, for this range of mass scales, the power spectrum is such that the higher torques acting on the higher density peaks dominate over the shorter collapse time during which torques can act. In order for the higher torque mechanism to dominate at the smaller mass scales, the slope of the power spectrum has to be shallow, possibly even shallower than that predicted for the CDM spectrum.