Newsletter Archive
|
EXTRA! EXTRA!
— Suzaku Shines Light on Black Hole Mysteries!
The adage says "good things come to those who wait". Patience, and a lot of hard work, tears, and tenacious persistence since the mid-1990s, are beginning to produce science results that were worth the wait. On Thursday, October 5, 2006, at a meeting of the High Energy Astrophysics Division of the American Astronomical Society in San Francisco, two teams of scientists presented exciting results that significantly improve our understanding of black holes. Both sets of findings were made possible by Suzaku's measurement of X-ray spectral lines at a greater resolution than ever before.
Due to the extreme energies around a black hole, X-rays are emitted in its accretion disk - the disk of matter that swirls around, and is gradually pulled into, the black hole. The X-ray "broad iron K" line indicates hot iron plasma in the presence of strong gravity, and it is proving to be an excellent measure of black hole properties. The extreme gravity of black holes stretches the line over a broader range of energy, providing much more detailed information.
A team lead by Andrew Fabian of Cambridge University in England studied a distant galaxy, MCG-6-30-15, known to have a supermassive black hole at its center. Supermassive black holes are in the core of most galaxies, and contain the mass of millions to billions of suns occupying an area the size of our solar system. The group was able to see, in greater detail than ever before, an amazing effect predicted by Einstein's general relativity: X-rays emitted close to the black hole and trying to escape are bent back around into the accretion disk as it flows toward the black hole.
The other team, lead by James Reeves of NASA Goddard Space Flight Center in Greenbelt, MD, studied MCG-5-23-16, another galaxy with a central supermassive black hole. The team was able to measure - for the first time - the angle of the accretion disk to the black hole's axis of spin. They determined that in this galaxy, the disk was inclined at a 45° angle. A measurement this precise was not possible before Suzaku.
More online information about these discoveries is available at http://suzaku-epo.gsfc.nasa.gov/docs/suzaku-epo/news/head.html.
Our next newsletter will feature these results in greater depth, along with ideas on how to use this science news in a classroom environment.
|
