Population of hot subdwarf stars studied with Gaia III. Catalogue of
  known hot subdwarf stars: Data Release 2
  In light of substantial new discoveries of hot subdwarfs by ongoing
spectroscopic surveys and the availability of new all-sky data from
ground-based photometric surveys and the Gaia mission Data Release 2, we
compiled an updated catalogue of the known hot subdwarf stars. The catalogue
contains 5874 unique sources including 528 previously unknown hot subdwarfs and
provides multi-band photometry, astrometry from Gaia, and classifications based
on spectroscopy and colours. This new catalogue provides atmospheric parameters
of 2187 stars and radial velocities of 2790 stars from the literature. Using
colour, absolute magnitude, and reduced proper motion criteria, we identified
268 previously misclassified objects, most of which are less luminous white
dwarfs or more luminous blue horizontal branch and main-sequence stars.
