White Dwarfs in the Era of the LSST and its Synergies with Space-Based
  Missions
  With the imminent start of the Legacy Survey for Space and Time (LSST) on the
Vera C. Rubin Observatory, and several new space telescopes expected to begin
operations later in this decade, both time domain and wide-field astronomy are
on the threshold of a new era. In this paper, we use a new, multi-component
model for the distribution of white dwarfs (WDs) in our Galaxy to simulate the
WD populations in four upcoming wide-field surveys (i.e., LSST, Euclid, the
Roman Space Telescope and CASTOR) and use the resulting samples to explore some
representative WD science cases. Our results confirm that LSST will provide a
wealth of information for Galactic WDs, detecting more than 150 million WDs at
the final depth of its stacked, 10-year survey. Within this sample, nearly
300,000 objects will have 5$\sigma$ parallax measurements and nearly 7 million
will have 5$\sigma$ proper motion measurements, allowing the detection of the
turn-off in the halo WD luminosity function and the discovery of more than
200,000 ZZ Ceti stars. The wide wavelength coverage that will be possible by
combining LSST data with observations from Euclid, and/or the Roman Space
Telescope, will also discover more than 3,500 WDs with debris disks,
highlighting the advantages of combining data between the ground- and
space-based missions.
