Extract from ABC News
In short:
Researchers claim to have discovered the first intermediate-mass black hole.
It was found about 18,000 light-years from our Solar System in our galaxy, the Milky Way.
What's next?
Astronomers believe more black holes of this kind will be found.
The discovery of a black hole 20,000 times bigger than the Sun could be a missing link to help astronomers understand supermassive black holes and how galaxies evolve.
This intermediate-mass black hole — detected in the Milky Way, 18,000 light-years away from our Solar System — is the first of its size to be confirmed to exist, research published in Nature today claims.
Black holes are extraordinarily dense objects with gravity so strong not even light can escape.
Before now, astronomers had confirmed the existence of only two kinds of black hole: stellar-mass black holes, which are up to 50 times the mass of our Sun, and supermassive black holes, which are up to a billion times bigger and believed to be at the centre of every large galaxy.
The mid-sized black hole was found in the Omega Centauri cluster.
"Astronomers have been looking for these so-called intermediate-mass black holes for 20 or 25 years," said University of Queensland Holger Baumgardt, one of a team of international researchers involved.
"Now, we have really found one, and convincingly demonstrated that this one exists."
Black holes of this size have so far been elusive and hard to confirm, according to Curtin University's Professor James Miller-Jones.
This research isn't the first to claim to have detected an intermediate-mass black hole, but the discovery may be the most robust to date, he said.
"Supermassive black holes are believed to co-evolve with their host galaxies, providing important feedback of gravitational energy to the larger galaxy, with the energetic jets that they launched believed to play a role in regulating star formation," Professor Miller-Jones, from the Curtin University node of the International Centre for Radio Astronomy Research, said.
"So understanding how supermassive black holes grow is important in helping us understand how galaxies evolve."
Omega Centauri is thought to be the remnant of a galaxy swallowed up by the Milky Way — an "old and dense" collection of stars that provides an "excellent environment" to hunt this type of black hole, Professor Miller-Jones said.
To find it, astronomers analysed and catalogued 1.4 million stars, looking for fast-moving stars that could indicate a concentrated mass — like a black hole.
Seven fast-moving stars led them to the intermediate-mass black hole.
Dr Baumgardt believes there are more to be found.
"There are a few other nearby systems which could also be the centres of former dwarf galaxies," Dr Baumgardt said.
"The next step is to also look in these systems and see if we find massive black holes in these systems as well, and should that be the case then maybe we really get an understanding how these supermassive black holes have formed."
No comments:
Post a Comment