  Two new families of exact solutions to the Einstein equations for a
conformastatic spacetime with axial symmetry are presented which describe thin
disks of dust immersed in a spheroidal halo. The solutions are obtained by
expressing the metric function in terms of an auxiliary function which
satisfies the Laplace equation, a characteristic property of the conformastatic
spacetimes. The first family of solutions is obtained from the displacement,
cut and reflexion method, which introduces a discontinuity in the first
$z$-derivate of the metric tensor across the plane of the disk. The second
family of solutions is obtained by using the oblate spheroidal coordinates
because they adapt to the shape of the source and introduce naturally a cutting
radius for the disk. The energy densities of the disk and the halo are
everywhere positive and well behaved and their energy-momentum tensor agrees
with all the energy conditions. Some particular solutions for the energy
density of the disk and the halo are presented and the rotational curves are
obtained by solving the geodesic equation for a particle that moves in circular
orbits in the plane of the disk.
