A SPECTROSCOPIC SURVEY OF FAINT QSOS

Positions, magnitudes and identifications are presented for a complete sample of 236 faint (B less-than-or-similar-to 22 mag) stellar objects based on spectroscopic observations of multicolour selected samples from deep photographic plates. Similar information is also provided for a further 98 objects not included in the complete sample. The survey covers an effective area of 0.85 deg2 and contains 66 newly identified QSOs. In total, 93 per cent of the complete sample has been identified and unambiguous redshifts have been obtained for 85 per cent of the QSOs. The integral surface density of low-redshift (z < 2.2) QSOs at B < 22 mag is estimated to be 67.6 +/- 8.8 deg2, confirming the strong flattening previously observed in the QSO number-magnitude relation at B greater-than-or-similar-to 19.5 mag. At the same magnitude limit, the integral surface density of QSOs in the range 2.2 < z < 2.9 is found to be 9.2 +/- 3.7 deg2. Broad absorption line systems are observed in 5-10 per cent of the QSOs in which such systems should be detectable, a similar percentage to those derived from brighter samples of QSOs. Emission line equivalent widths measured in this survey are similar to those derived from optically brighter QSO samples. The remainder of the survey is principally composed of galactic subdwarf stars and compact narrow emission line galaxies, although six DA white dwarfs and eight distant ( > 35 kpc) blue horizontal branch stars are also identified.