The IPHAS-POSS-I proper motion survey of the Galactic plane

We present a proper motion survey of the Galactic plane, using Isaac Newton Telescope (INT) Photometric Hα Survey (IPHAS) data and Palomar Sky Survey (POSS)-I Schmidt plate data as a first epoch, that probes down to proper motions below 50 mas yr ^-1. The IPHAS survey covers the northern plane (|b| < 5°) with CCD photometry in the r, i and Hα passbands. We examine roughly 1400 deg ² of the IPHAS survey area and draw up a catalogue containing 103 058 objects with significant proper motions below 150 mas yr ^-1 in the magnitude range 13.5 < r′ < 19. Our survey sample contains large samples of white dwarfs and subdwarfs which can be identified using a reduced proper motion diagram. We also found several objects with IPHAS colours suggesting Hα emission and significant proper motions. One is the known cataclysmic variable GD552; two are known DB white dwarfs and five others are found to be non-DA (DB and DC) white dwarfs, which were included in the Hα emission line catalogue due to their lack of absorption in the Hα narrow band.