Decomposition of the rotation curves of distant field galaxies

Abstract

We present decompositions of the rotation curves of distant spiral galaxies into contributions due to their bulges, disks, and putative dark haloes. In order to set constraints on the ambiguities of the decompositions we interpret the morphology of the spiral structures quantitatively in the framework of density wave theory. Galaxy models constrained in such a way show that the distant galaxies, which are much younger than nearby galaxies, are indeed also imbedded in dark haloes as expected from contemporary theories of the cosmonogy of galaxies.