3C 336

Description

3C 336 is a steep radio spectrum radio-loud quasar at the center of a rich galaxy cluster. Its spectrum shows six metal absorption lines at redshifts of 0.472, 0.797, and 0.891, associated with absorbing galaxies including an early-type spiral galaxy and a faint complex galaxy. A damped Lyman-alpha absorber at redshift 0.656 has an H I column density of 2 × 10^20 cm−2. The radio structure is a double source with each component smaller than 7 × 4 arcseconds and no interplanetary scintillations. A total intensity image reveals an asymmetric source spanning 28 milliarcseconds with two radio lobes. A jet composed of bright knots extends southwest, linking a compact component to an elongated recessed feature in the southern lobe. No counterjet is seen, but a conspicuous knot lies on the jet axis, followed by a hook of radio emission curving toward a bright ridge on the eastern side of the northern lobe. The nucleus contains a core component of 12 Jansky at position angle 200°, with a resolved low-surface brightness extension. High-resolution Very Large Array and MERLIN observations show radio emission from the lobes extending back into the core and jet. A compact hotspot in the southern lobe has flux densities of 0.097 ± 0.015 Jy at 1.53 GHz and 0.045 ± 0.007 Jy at 4.89 GHz, with an optical spectrum of 1.5 ± 1.0. At 0.35 arcsecond resolution, the hotspot splits into two compact components, one aligned with the jet and core, the other offset. The emission-line region, observed with Hubble Space Telescope and ground-based imaging, is asymmetric with a low-surface brightness structure northwest perpendicular to the radio axis, though later data indicate emission mainly restricted to the south with a flux of 1.8 ± 0.5 × 10^−16 erg cm−2 s−1. Optical emission extends 5 arcseconds north and 3 arcseconds south from the quasar, with a velocity shear of 600 kilometers per second across the emission.