Identification of PKS 0438-43, a quasar with the highest known radio luminosity.

Summary. The strong radio source PKS 0438-43 has been identified with a faint QSO having an emission redshift z = 2.852. Both and C iv have unusually sharp peaks. At least three strong absorption lines are superposed on Lo emission, and two of them are at longer wavelengths. The radio flux is 7.0Jy at 1GHz, varies as from 0.15 to 5GHz, and drops to 3.0Jy at 14.7GHz. If the distance is cosmological, the radio luminosity is about 2 x 10 erg/s (H0 =50 km i Mpc1, q0 =0) making this one of the most luminous known radio objects. The optical flux at 4400 A is 3.9 x l0- Jy, (B = 19.8) and the continuum varies as . Over the observed band from 4000 to 7000 A the optical luminosity is about one-quarter of the radio power.