Evaluating the disk formation paradigm in the LCDM framework: constraints from the Milky Way

Abstract

We investigate the properties of a galaxy similar to the Milky Way within the context of standard disk formation theory in a LCDM universe. Using the standard assumption that baryons conserve specific angular momentum when they collapse, we conclude that the mean properties of the model galaxies are in good agreement with the Milky Way and other similar spiral galaxies, but the predicted scatter in disk scale lengths may be too large. A model in which half of the initial specific angular momentum is transfered to the dark matter may produce a smaller scatter, if very compact disks are unstable and evolve into spheroids or early type galaxies.