EVIDENCE FOR ORDERED MAGNETIC-FIELDS IN THE QUASAR ENVIRONMENT

At a distance of 20 pc from the purported supermassive black hole powe ring quasars, temperatures and densities are inferred from optical obs ervations (Osterbrock) to be similar to 10(4) K and similar to 10(4) c m(-3). Here we present very long baseline interferometry radio observa tions revealing organized magnetic fields on the parsec scale in the h ot plasma surrounding the quasar OQ 172 (1442+101). These magnetic fie lds rotate the plane of polarization of the radio emission coming from the core and inner jet of the quasar. The derived rotation measure (R M) is 40,000 rad m(-2) in the rest frame of the quasar. Only 10 mas (a projected distance of 68 pc) from the nucleus, the jet absolute value s of RM fall to less than 100 rad m(-2).