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Seyfert Galaxies

A Seyfert is a spiral or barred-spiral galaxy with a bright compact nucleus. In short exposure images, the outer parts of the galaxy are not seen and the nucleus appears almost star-like, so that, in this respect, a Seyert nucleus resembles a quasar. Although not usually strong radio emitters, Seyfert nuclei radiate strongly over a wide range of wavelength producing strong gamma-ray emission up to 1 million ev. Its intensity peaks at an emission line near 450 nm They are less luminous than quasars, but are brighter than
Seyfert galaxy Face-on Seyfert galaxy Edge-on most normal spirals (about 100 times more luminous than the Milky Way). Across the spectrum, the tremendous brightness of Seyferts can change over periods of just days to months and Seyfert galaxies like NGC 7742 in Figure 05-03a are suspected of harboring massive black holes at their cores. Figure 05-03b shows the edge-on view of another Seyfert galaxy M106, which conveys an impression that matters are falling into a hole.

Figure 05-03a Seyfert Galaxy Face-on [view large image]

Figure 05-03b Seyfert Galaxy Edge-on [view large image]

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