A search for white dwarfs in the Galactic plane: the field and the open
  cluster population
  We investigated the prospects for systematic searches of white dwarfs at low
Galactic latitudes, using the VLT Survey Telescope (VST) H$\alpha$ Photometric
Survey of the Galactic plane and Bulge (VPHAS+). We targeted 17 white dwarf
candidates along sightlines of known open clusters, aiming to identify
potential cluster members. We confirmed all the 17 white dwarf candidates from
blue/optical spectroscopy, and we suggest five of them to be likely cluster
members. We estimated progenitor ages and masses for the candidate cluster
members, and compared our findings to those for other cluster white dwarfs. A
white dwarf in NGC 3532 is the most massive known cluster member (1.13
M$_{\odot}$), likely with an oxygen-neon core, for which we estimate an
$8.8_{-4.3}^{+1.2}$ M$_{\odot}$ progenitor, close to the mass-divide between
white dwarf and neutron star progenitors. A cluster member in Ruprecht 131 is a
magnetic white dwarf, whose progenitor mass exceeded 2-3 M$_{\odot}$. We stress
that wider searches, and improved cluster distances and ages derived from data
of the ESA Gaia mission, will advance the understanding of the mass-loss
processes for low- to intermediate-mass stars.
