We search for ultraluminous Quasi-Stellar Objects (QSOs) at high redshift using photometry from the SkyMapper Southern Survey Data Release 3 (DR3), in combination with 2MASS, VHS DR6, VIKING DR5, AllWISE, and CatWISE_2020_, as well as parallaxes and proper motions from Gaia DR2 and eDR3. We report 142 newly discovered Southern QSOs at 3.8 < z < 5.5, of which 126 have M_145_ 80 per cent complete for M_145_ < -27.33 AB mag at z = 4.7 and for M_145_ < -27.73 AB mag at z = 5.4. We derive the bright end of the QSO luminosity function at rest frame 145 nm for z = 4.7-5.4 and measure its slope to be {beta} = -3.60 +/- 0.37 and {beta} = -3.38 +/- 0.32 for two different estimates of the faint-end QSO density adopted from the literature. We also present the first z ~ 5 QSO luminosity function at rest frame 300 nm.
Cone search capability for table J/MNRAS/511/572/table1 (List of newly discovered QSOs with redshifts between 3.8 <= z < 4.4)
Cone search capability for table J/MNRAS/511/572/table2 (List of newly discovered QSOs with redshifts between 4.4 <= z < 4.7)
Cone search capability for table J/MNRAS/511/572/table3 (List of newly discovered QSOs with redshifts between 4.7 <= z < 5.5)