We present a highly complete and reliable mid-infrared (MIR) colour selection of luminous
active galactic nucleus (AGN) candidates using the 3.4, 4.6 and 12 μm bands of the Wide-
field Infrared Survey Explorer (WISE) survey. The MIR colour wedge was defined using the
wide-angle Bright Ultrahard XMM–Newton survey (BUXS), one of the largest complete flux-
limited samples of bright ()'ultrahard'(4.5–10 keV) X-ray-selected AGN to date. The BUXS
includes 258 objects detected over a total sky area of 44.43 deg2 of which 251 are …

We present a highly complete and reliable mid-infrared (MIR) colour selection of luminous
active galactic nucleus (AGN) candidates using the 3.4, 4.6 and 12 μm bands of the
Widefield Infrared Survey Explorer (WISE) survey. The MIR colour wedge was defined using
the wide-angle Bright Ultrahard XMM–Newton survey (BUXS), one of the largest complete
flux-limited samples of bright (f4. 5–10 keV> 6× 10− 14 erg s− 1 cm− 2)'ultrahard'(4.5–10
keV) X-ray-selected AGN to date. The BUXS includes 258 objects detected over a total sky …