  The Sombrero galaxy (NGC 4594) is an Sa galaxy with a symmetric dust ring. We
have used the Large APEX BOlometer CAmera (LABOCA) at 870 micron and the
MAx-Planck Millimeter BOlometer (MAMBO-2) at 1.2 mm to detect the dust ring for
the first time at submillimetre and millimetre wavelengths. We have constructed
a model of the galaxy to separate the active galactic nucleus (AGN) and dust
ring components. The ring radius at both 870 micron and 1.2 mm agrees well with
the radius determined from optical absorption and atomic gas studies. The
spectral energy distribution of the ring is well fitted by a single grey-body
with dust emissivity index beta=2 and a dust temperature T_d=18.4 K. The dust
mass of the ring is found to be 1.6\pm0.2x10^7Msun which, for a Galactic
gas-to-dust ratio, implies a gas mass that is consistent with measurements from
the literature.
