RAS: Black holes and galaxy death

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bystander
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RAS: Black holes and galaxy death

Post by bystander » Thu Apr 15, 2010 11:27 pm

Black holes and galaxy death
Royal Astronomical Society Press Release
RAS PN 10/37 (NAM 22) 16-Apr-2010
Black holes are thought to reside at the centre of almost every galaxy, with some growing to more than a billion times the mass of the Sun. Now a team of UK astronomers believe that these supermassive black holes are commonplace, release more than enough energy to strip their host galaxies apart and in the process shut down these galaxies' star formation for good. ...

For many years black holes have fascinated scientists and the public alike, with their peculiar ability to warp space and time and their almost sinister tendency to devour everything they encounter. Before it falls in, as matter swirls around the black hole it forms an "accretion disk", where it heats up and radiates energy. The supermassive black holes have such a strong gravitational field that the infalling matter releases a vast amount of energy, making each accretion disk far brighter than the combined output of the hundreds of billions of stars in the galaxy around it.

One of the consequences of this outpouring of energy is that it drives away cool gas and dust, the raw ingredients of new stars. This permanently shuts down star formation in the surrounding galaxy, dooming it to a slow death, where the remaining stars age, grow red, end their lives and are never replaced.
Image
The image is a multi-wavelength image of the galaxy NGC 1275 which is a local equivalent to many of the
distant massive galaxies studied by Asa Bluck and the other members of the Nottingham / University
College London team. It shows the phenomenal power of supermassive Black Holes to rearrange the gas
of a galaxy, and represents a window onto a violent past to the lives of galaxies. Over the history of
the Universe at least 1/3 of all galaxies went through a phase of development similar to this one.
(A. Fabian (Cambridge)/STScI/NASA)