Thursday, September 09, 2010

Binge eating black holes eventually commit suicide

Death is a fact of life; even for galaxies.

It can happen when massive galaxies collide, or it can be predetermined by the conditions the galaxies formed under. But new observations published by the journal Astronomy and Astrophysics show that black holes at the centers of galaxies can strip precious star forming material from the surrounding area and hurl it out into the blackness of space, eventually robbing the galaxy of what it needs to produce new stars.

From the paper:
"The depletion of gas resulting from quasar driven outflows should eventually stop star formation across the host galaxy and lead to 'suicide' by starvation."
In the research, which was released last month, astronomers from France and Italy used the Plateau de Bure Interferometer in the French Alps to observe a distant galactic center expel as much as 700 solar masses of material from the galaxy per year.

It recent years, observations have shown that supermassive black holes exist at the center of many galaxies and even play a part in galactic evolution. And while it's widely known that black holes suck in stars that venture too close, they also heat up the surrounding gas and dust required for star formation. As they do, the formerly cold gas around these cosmic vacuum cleaners begins to glow.

Finally, once the supermassive black hole has reached a mass millions of times larger than the sun, it heats the gas enough that it actually spews from the solar system in great winds that slowly rob the galaxy of future worlds and future black hole food. The group estimates if the galaxy loses 700 solar masses of this molecular gas every year, within 140 million years star formation wouldn't be possible and they observe that the central regions closer to the black hole are already devoid of young stars.

According to the astronomers, the observations also help solve two cosmic mysteries; why there are so many fewer large galaxies than what computer models would predict, and why so many galaxies are colored red - an indication of old star populations.

You can read a copy of the paper here.

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