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Paper: Free-Free Absorption towards Active Galactic Nuclei
Volume: 340, Future Directions in High Resolution Astronomy: The 10th Anniversary of the VLBA
Page: 145
Authors: Kameno, S.; Inoue, M.; Wajima, K.; Shen, Z.-Q.; Sawada-Satoh, S.
Abstract: We report results from multifrequency observations for 18 GHz-Peaked Spectrum (GPS) sources, which show convex radio spectra due to Free-Free Absorption (FFA). Trichromatic VLBA observations showed that radio galaxies and Seyfert-2 sources tend to show symmetric opacity distributions along double-sided jets while asymmetric profiles are found in QSO and Seyfert-1. The significant difference can be related to the orientation of the jets. Pentachromatic VSOP and VLBA observations for the nearest object, NGC 1052, revealed spatial distribution of cold dense plasma around the nucleus are obtained via opacities of FFA. The density distribution indicates a dense disk or torus of ∼ 1 pc in radius.
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