Monday, November 30, 2009

Supermassive black hole

Astronomers have captured a distant black hole creating the galaxy that will eventually become its home.

By sending a jet of gas into a neighboring galaxy, the black hole has touched off star formation at a rate 100 times the galactic average.

“Our study suggests that supermassive black holes can trigger the formation of stars, thus ‘building’ their own host galaxies,” David Elbaz, lead author of a paper on the work in the journal Astronomy and Astrophysics, said in a press release. “This link could also explain why galaxies hosting larger black holes have more stars.”

The quasar HE0450-2958, located about five billion light-years from Earth, is powered by a supermassive black hole. Unlike all other known quasars, this one did not appear to be surrounded by a galaxy, which had puzzled astronomers. They thought perhaps the quasar’s surrounding galaxy was obscured by dust. So in the latest observations they looked in the mid-infrared part of the spectrum, in which dust shines brightly, using the European Southern Observatory’s Very Large Telescope. But they didn’t see dust, confirming the idea that the quasar really is “naked.”

Instead of a surrounding galaxy, Elbaz’s team found the black hole was blasting its neighbor with energy and matter. That injection has caused the observed flurry of star births. 350 new suns are bursting into existence each year in the region.

Eventually, the black hole will merge with its neighbor. The two objects are located 22,000 light-years apart and are moving towards each other at less than 125 miles per second. In tens of millions of years, HE0450-2958 will finally get a home.

“This would provide a natural explanation for the missing host galaxy,” Elbaz and his co-authors wrote.

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