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Paper: Unification of 3CR Radio Galaxies and Quasars
Volume: 373, The Central Engine of Active Galactic Nuclei
Page: 499
Authors: Schulz, B.; Siebenmorgen, R.; Haas, M.; Kruegel, E.; Chini, R.
Abstract: We have observed seven powerful FR2 radio galaxies and seven quasars with the Spitzer IRS (Houck et al. 2004). Both samples are comparable in both redshift range and isotropic 178 Hz luminosity. Both samples are found to have similar distributions in the luminosity ratios of mid-IR high- and low-excitation lines ([NeV]/[NeII]), and of mid-IR high-excitation line to radio power ratio ([NeV]/P178 MHz). However, the MIR/FIR ratio is generally higher for quasars. We further observed Silicate features at 10 and 18 μm in emission. In our sample only quasars show emission features, while silicate absorption is seen only in the radio galaxies. These observations are all in agreement with unification schemes that explain both groups as the same class of objects seen under different orientation angles.
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