2006MNRAS.369.1566G

We present new X-ray and optical spectroscopy of a type 2 quasar candidate selected from a follow-up programme of hard, optically dim, serendipitous Chandra sources. The source is confirmed to be a type 2 quasar at z = 0.536 with an intrinsic 2-10 keV luminosity L_2–10= 5x10⁴⁴h^–2_0.7erg/s, an absorbing column density N_H= 8x10²³/cm2 and a neutral Fe Kα line detected by XMM-Newton EPIC-MOS1 as well as Chandra ACIS-S. An extended optical forbidden emission-line cloud is detected at the same redshift, and at about 15 kpc in projected separation. This cloud lies in close proximity to the peak of the compact steep spectrum radio source 4C +39.29, which has previously been identified with a foreground galaxy in the cluster Abell 963. We present evidence to show that 4C +39.29 is associated with the background X-ray type 2 quasar. The radio luminosity is dominated by lobes with complex structure and the radio core is weak in comparison to narrow-line radio galaxies at the same X-ray luminosity. The morphology and emission-line properties of the extended region are consistent with an ongoing jet-cloud interaction. 4C +39.29 possesses a combination of high power and high absorbing column density compared with other X-ray type 2 quasars in the literature. These observations highlight the efficacy of using X-rays to identify the primary energy source of complex radio sources and distant obscured active galactic nuclei.