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Astronomers may have discovered a massive black hole

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11.11.2005

Astronomers from British and German universities have made a new discovery which could provide evidence for a previously unknown supermassive black hole millions of times heavier than the sun.

The team from the Centre for Astrophysics Research at the University of Hertfordshire and at the Dr Remeis-Sternwarte at the University of Erlangen-Nuernberg/D have discovered a short-lived massive star, named HE 0437-5439, that is moving at a very high speed through the outer halo of the Milky Way galaxy and into intergalactic space, which has led them to suspect the existence of the black hole.

The discovery was part of the team’s Hamburg-ESO sky survey and observed with the 8.2m Kueyen of the ESO Very Large Telescope observatory on Cerro Paranal in Chile.

The finding has come as a big surprise to the astronomers as massive stars have lifetimes of only some tens or hundreds of million years and the halo does not usually host stars as young as HE 0437-5439, which the team has estimated is 30 million years old.

The position of the star in the sky has raised many questions as to how it came to be in its present location. Stars can be ejected by supermassive black holes as the one known in the centre of our Milky Way. However, a Milky Way origin of HE 0437-5439 is unlikely.

This has led the astronomers to suspect that the star could have travelled its current distance if it were ejected from the centre of the Large Magellanic Cloud (LMC), from where at the time of the observation it was 16 degrees away.

The astronomers look forward to having these and other questions answered by forthcoming astrometric space missions such as GAIA which is due to be launched in 2011.

Work on this project was supported by the Particle Physics Astronomy Council (PPARC) and the Deutsche Forschungsgemeinschaft (DFG).

Helene Murphy | Source: alphagalileo
Further information: www.herts.ac.uk

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