1. Revealing the Heavily Obscured Active Galactic Nucleus Population of High-Redshift 3crr Sources With Chandra X-Ray Observations
- Author
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Wilkes, Belinda Jane, Kuraszkiewicz, Joanna, Haas, Martin, Barthel, Peter, Leipski, Christian, Willner, Steven P., Worrall, Diana M., Birkinshaw, Mark, Antonucci, Robert, Ashby, Matthew L N, Chini, Rolf, Fazio, Giovanni Gene, Lawrence, Charles, Ogle, Patrick, and Schulz, Bernhard
- Subjects
Quasars: general ,X-rays: galaxies - Abstract
Chandra observations of a complete, flux-limited sample of 38 high-redshift (1
0) indicating obscuration (NH ∼ 1022–1024 cm−2). These properties and the correlation between obscuration and radio core fraction are consistent with orientation-dependent obscuration as in unification models. About half the NLRGs have soft X-ray hardness ratios and/or a high [O iii] emission line to X-ray luminosity ratio suggesting obscuration by Compton thick (CT) material so that scattered nuclear or extended X-ray emission dominates (as in NGC 1068). The ratios of unobscured to Compton-thin (1022 cm−2 < NH(int) < 1.5 × 1024 cm−2) to CT (NH(int) > 1.5 × 1024 cm−2) is 2.5:1.4:1 in this high-luminosity, radio-selected sample. The obscured fraction is 0.5, higher than is typically reported for active galactic nuclei at comparable luminosities from multi-wavelength surveys (0.1–0.3). Assuming random nuclear orientation, the unobscured half-opening angle of the disk/wind/torus structure is ∼60◦ and the obscuring material covers 30◦, ∼12◦ of which is CT. The multi-wavelength properties reveal that many NLRGs have intrinsic absorption 10–1000× higher than indicated by their X-ray hardness ratios, and their true LX values are ∼10–100× larger than the hardness-ratio absorption corrections would indicate., Astronomy - Published
- 2013
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