Increasing exposure photographs of NGC 4151, showing a prominent (blue) nucleus. Visually, this galaxy appears to have a blue star in its nucleus. (From Morgan 1968 ApJ 153, 27)
Basic Observational Features of Seyferts |
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Increasing exposure photographs of NGC 4151, showing a prominent (blue) nucleus. Visually, this galaxy appears to have a blue star in its nucleus. (From Morgan 1968 ApJ 153, 27)
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Optical spectra of three Seyfert galaxies that illustrate the transition from Seyfert 1 (top) to Seyfert 2 (bottom). The classification focuses on the relative strength of the broad hydrogen lines, compared to the narrow forbidden oxygen lines. |