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Session 12 - Radio Galaxies, VLBI.
Display session, Monday, January 15
North Banquet Hall, Convention Center

[12.08] A Precessing Beam in Radio Quasar 0153+744

C. A. Hummel (USRA), T. P. Krichbaum, A. Witzel (MPIfR), W. Steffen (U. of Manchester)

We present new high resolution VLBI maps of the radio structure of quasar 0153+744 (z=2.34) at \lambda\lambda 6\,cm and 1.3\,cm, showing its jet to undergo a full 180 degree turn between the core component (A) and a bright secondary component (B) only 10 milliarcseconds away. Using maps published for earlier epochs, we conclude that component B is stationary and place an upper limit of 0.5\,c (H_0=100\,km/s/Mpc, q_0=0.5) on any apparent motion. No component motions are found in the jet either. The core is resolved at 1.3\,cm wavelength into a core-jet structure with four distinct components, whereas B consists of diffuse emission. Using B as a reference position, we measure a dependence of the core peak brightness position with wavelength. No extended emission is found on scales larger than about 1 arcsecond from VLA maps made at 20\,cm in A and C configuration. We discuss a model of a mildly relativistic precessing jet for the 0153+744, and show that a reasonable fit to the observed properties of the radio structure is achieved.

Program listing for Monday