Article Posted on : - Sep 17, 2008

LONDON (BNS): Once thought to be exotic and rare, Black Holes are known to exist through the length and breadth of the whole Universe. The largest and ultra massive ones, found at the centre of the largest Galaxies, have a mass that is more than one billion times that of the Sun.

According to new research conducted by Priyamvada Natarajan, an associate professor of astronomy and physics at Yale University and a fellow at the Radcliffe Institute for Advanced Study has shown that even the biggest of these gravitational monsters can't keep growing forever. “Instead, they appear to curb their own growth, once they accumulate about 10 billion times the mass of the Sun,” astronomer Natarajan said.

Elaborating on the discovery, the astronomer said that these ultra-massive black holes, found at the centres of giant elliptical galaxies in huge galaxy clusters, are the biggest known in the Universe. It is said that even the large black hole at the centre of the Milky Way galaxy is thousands of times less massive than these ‘ultra-massive’ black holes.

But, it has been noted that these gigantic black holes, which accumulate mass by sucking in matter from neighbouring gas, dust and stars, seem unable to grow beyond this limit regardless of where and when they appear in the Universe. “It's not just happening today and they shut off at every epoch in the Universe,” Natarajan said.

To put forth her theory, Natarajan used the existing optical and X-ray data of the ultra-massive black holes to point out that, in order for those various observations to be consistent, the black holes must essentially shut off at some point in their evolution.

Natarajan explaining further said that the black holes eventually reach the point when they radiate so much energy as they consume their surroundings that they end up interfering with the very gas supply that feeds them, which may interrupt nearby star formation. She said that the new findings would have implications in the future study of galaxy formation, since many of the largest galaxies in the Universe appear to co-evolve along with black holes at the centres.

Speaking about the new discovery, Natarajan said, “Evidence has been mounting for the key role that black holes play in the process of galaxy formation. But it now appears that they are like the prima donnas of the space opera.”