On the origin of the angular momentum of galaxies: cosmological tidal torques supplemented by the Coriolis force

Abstract

We present here a theoretical model which can at least contribute to the observed relation between the specific angular momenta of galaxies and their masses. This study offers prima facie evidence that the origin of angular momentum of galaxies could be somewhat more complex than previously proposed. The most recent observations point to a scenario in which, after recombination, matter was organized around bubbles (commonly termed voids), which acquired rotation by tidal torque interaction. Subsequently a combination of the effects of the gravitational collapse of gas in protogalaxies and the Coriolis force due to the rotation of the voids could produce the rotation of spiral galaxies. Thereafter the tidal interaction between the objects populating the quasi-spherical voids, in which the galaxies far away from the rotation axes (populating the sheet forming the surface of a void) interact with higher probability with others similarly situated in a neighbouring void, offers a mechanism for transforming some of the galaxies into ellipticals, breaking their spin and yielding galaxies with low net angular momentum, as observed. This model gives an explanation for those observations which suggest a tendency of galactic spins to align along the radius vectors pointing towards the centres of the voids for ellipticals/SO and parallel to filaments and sheets for the spirals. Furthermore, while in simple Tidal Torque Theory the angular momentum supplied to galaxies diminishes drastically with the cosmic expansion, in our approximation for which the Coriolis force acts in addition to tidal torques, the Coriolis force due to void rotation ensures almost continuous angular momentum supply.