Using the deepest and finest resolution images of the Universe acquired with the Hubble Space Telescope and a similar image taken 7 years later for the Great Observatories Origins Deep Survey , we have derived proper motions for the point sources in the Hubble Deep Field–North .
Two faint blue objects , HDF2234 and HDF3072 , are found to display significant proper motion , 10.0 \pm 2.5 and 15.5 \pm 3.8 mas yr ^ { -1 } .
Photometric distances and tangential velocities for these stars are consistent with disk white dwarfs located at \sim 500 pc .
The faint blue objects analyzed by Ibata et al .
( 1999 ) and Mendez & Minniti ( 2000 ) do not show any significant proper motion ; they are not halo white dwarfs and they do not contribute to the Galactic dark matter .
These objects are likely to be distant AGN .