We place observational constraints on a recently proposed Galactic population , dubbed the shroud ( Gyuk & Gates 1999 , Gates & Gyuk 2001 ) .
The shroud would be a very thick Galactic disk of low luminosity objects , most likely old white dwarfs , proposed to explain the optical depth seen in microlensing surveys towards the Magellanic clouds .
The shroud is a simple alternative to the lenses being distributed in a classical , near-spherical dark halo ; the advantage of the shroud is that it would compose only a fraction of a dark halo ’ s total mass .

In this paper , we argue that stars of the Galactic shroud would be detectable in the recent proper motion survey of Oppenheimer et al .
( 2001 ) if their absolute luminosities were brighter than M _ { R _ { 59 F } } = 19.4 or approximately M _ { V } = 18.6 .
We adopt a range of simple models of the shroud ’ s kinematics and morphology , and the colours and luminosities of its white dwarfs ; via Monte-Carlo simulations , we predict the numbers expected in the Oppenheimer et al .
survey , which would be clearly separated from the numbers produced by white dwarfs of the disk , thick disk and halo .

The number of white dwarf detections in the proper motion survey ( 98 ) is found to be well explained by the disk , thick disk and halo .
With the most conservative kinematic and density parameters for the shroud , and an absolute luminosity of the white dwarfs of M _ { R _ { 59 F } } = 17.6 , we find that the proper motion survey would detect over 100 WDs , just from the shroud .
For a M _ { R _ { 59 F } } = 19.4 shroud , the survey would find 5 \pm 2 peculiar objects , whereas only two white dwarfs with such characteristics are found in the original data . M _ { R _ { 59 F } } = 19.4 corresponds to M _ { V } = 18.6 for WDs with ( V - I ) = -1.030 .