Discovery of Active Galaxies
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Transcript: Active galaxies were discovered even before we knew the distance to galaxies. In 1908, Edward Fath discovered strong emission lines from the central regions of the galaxy NGC 1068. It indicated ionized gas, but a much larger amount of nuclear ionized gas than would exist in a normal star formation region. Vesto Slipher and Edwin Hubble found other examples, and Carl Seyfert conducted the first systematic survey in the 1940s. Seyfert also noted other common features of active galaxies: a high-contrast, compact nucleus, broad emission lines, strong radio emission, and peculiar morphology of the galaxy itself.
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