6 − 5 ) Observations of the Quasar SDSS 1044 − 0125 at z = 5 . 8

We present a result of the quasar CO(J = 6− 5) observations of SDSSp J104433.04−012502.2 at z = 5.8. Ten-days observations with the Nobeyama Millimeter Array yielded an rms noise level of ∼ 2.1 mJy beam in a frequency range from 101.28 GHz to 101.99 GHz at a velocity resolution of 120 km s. No significant clear emission line was detected in the observed field and frequency range. Three sigma upper limit on the CO(J =6−5) luminosity of the object is 2.8 ×10 K km s pc, corresponding to a molecular gas mass of 1.2× 10M⊙, if a conversion factor of 4.5 M⊙ (K km s pc) is adopted. The obtained upper limit on CO luminosity is slightly smaller than those observed in quasars at z = 4− 5 toward which CO emissions are detected.