We present X-ray and optical observations of CXOMP J213945.0-234655 , a high redshift ( z = 4.93 ) quasar discovered through the Chandra Multiwavelength Project ( ChaMP ) .
This object is the most distant X-ray selected quasar published , with a rest-frame X-ray luminosity of L _ { X } = 5.9 \times 10 ^ { 44 } erg s ^ { -1 } ( measured in the 0.3–2.5 keV band and corrected for Galactic absorption ) .
CXOMP J213945.0-234655 is a g ^ { \prime } dropout object ( > 26.2 ) , with r ^ { \prime } = 22.87 and i ^ { \prime } = 21.36 .
The rest-frame X-ray to optical flux ratio is similar to quasars at lower redshifts and slightly X-ray bright relative to z > 4 optically-selected quasars observed with Chandra .
The ChaMP is beginning to acquire significant numbers of high redshift quasars to investigate the X-ray luminosity function out to z \sim 5 .