Skywatch

  • July 26, 2012

    Episode 405: How Quasars Grow

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    Shownotes

    When we think of quasars, we envision brilliant, energetic objects, produced by black holes, that are the result of collisions of large galaxies. But not all quasars are exceedingly bright and the black holes that produce them can be more modest in size. How does this occur? A new study with observations from NASA's Spitzer Space Telescope and the Hubble Space Telescope suggest that fainter quasars are more common. The study also reveals that modest-sized black holes consume smaller amounts of gas and dust as well as small companion satellites, feeding the black hole and perhaps eventually producing a quasar.