PKS-1251-407 - A RADIO-LOUD QUASAR AT Z=4.46

During the course of a search for z > 5 radio-loud quasars, the radio source PKS 1251 - 407 was found to be identified with a quasar at z = 4.46. This is the highest redshift radio-loud quasar found to date, an d one of only two at z > 4. It has B and Gunn-i magnitudes of m(B) = 2 3.7 and m(i) = 19.9, and a flux density at 2.7 GHz of 0.25 Jy. The cor responding luminosities are typical of radio-loud quasars at lower red shifts. The Lya, N v and C Iv emission lines are exceptionally narrow, even for the class of narrow-line QSOs. It is likely that PKS 1251 - 407 is the highest redshift quasar in the parent sample of 896 nat-spe ctrum Parkes sources, and this would be consistent with a fall-off in the space density of such objects at high redshifts.