Active galaxies and rare objects

This image is an artist's impression of an active galaxy.  The centres of these galaxies are known to be extremely bright, emitting lots of energetic energy at X-rays. These jets are powered by supermassive black holes in the centre and travel out to great distances at speeds close to the speed of light.  These galaxies have a very bright active core embedded in what is otherwise an ordinary galaxy. Three main types are called Seyferts, quasars, and blazars. Although these types look different to us, astronomers believe these are the same object but viewed from different directions. Quasars are active galaxies which are all extremely far away from us (and therefore from a long time ago). Astronomers have seen quasars 12 billion light years away! The black hole at the centre of the active galaxy is thought to affect the growth and formation of stars in the galaxy itself. The powerful radiation and winds from the black hole are thought to 'shut-down' star formation and prevent the galaxy from growing ever larger. Herschel ATLAS should detect about 500 quasars and other rare active galaxy types and since Herschel sees the hidden star formation activitiy, our observations of active galaxies should shed light on how the black holes are influencing the galaxy growth process.

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