Tuesday, July 30, 2013

Why Do Black Holes And Galaxies Spin?

Astronomers have found a new way of measuring the spin in supermassive black holes, which could lead to better understanding about how they drive the growth of galaxies. The scientists at Durham University, UK, publish their work in a paper in the Oxford University Press journal Monthly Notices of the Royal Astronomical Society.

The team of astronomers observed a black hole - with a mass 10 million times that of our Sun - at the center of a spiral galaxy 500 million light years from Earth while it was feeding on the surrounding disc of material that fuels its growth and powers its activity.

By viewing optical, ultra-violet and soft x-rays generated by heat as the black hole fed, they were able to measure how far the disc was from the black hole.

This distance depends on black hole spin as a fast spinning black hole pulls the disc in closer to itself, the researchers said. Using the distance between the black hole and the disc, the scientists were able to estimate the spin of the black hole.

The scientists said that understanding spin could lead to greater understanding of galaxy growth over billions of years.

Black holes lie at the centers of almost all galaxies, and can spit out incredibly hot particles at high energies that prevent intergalactic gases from cooling and forming new stars in the outer galaxy. Scientists don't yet understand why the jets are ejected into space, but the Durham experts believe that their power could be linked to the spin of the black hole. This spin is difficult to measure as it only affects the behavior of material really close to the black hole.

An artist’s impression of a supermassive black hole at the centre surrounded by matter flowing onto the black hole in what is termed an accretion disk. Also shown is an outflowing jet of energetic particles, believed to be powered by the black hole's spin.
Image credit: NASA/JPL-Caltech  

Lead researcher Professor Chris Done, in the Department of Physics, at Durham University, said: "We know the black hole in the centre of each galaxy is linked to the galaxy as a whole, which is strange because black holes are tiny in relation to the size of a galaxy. This would be like something the size of a large boulder (10m), influencing something the size of the Earth.

"Understanding this connection between stars in a galaxy and the growth of a black hole, and vice-versa, is the key to understanding how galaxies form throughout cosmic time.

"If a black hole is spinning it drags space and time with it and that drags the accretion disc, containing the black hole's food, closer towards it. This makes the black hole spin faster, a bit like an ice skater doing a pirouette.

"By being able to measure the distance between the black hole and the accretion disc, we believe we can more effectively measure the spin of black holes.

"Because of this, we hope to be able to understand more about the link between black holes and their galaxies."

The Durham scientists were able to measure the spin of the black hole using soft x-ray, optical and ultra-violet images captured by the European Space Agency's XMM-Newton satellite.


Contacts and sources:
Professor Chris Done
Department of Physics
Durham University
Royal Astronomical Society   

1 comment:

  1. The very space-time concept, on which theories of relativity are founded, has been mathematically, theoretically & experimentally proved as baseless and openly challenged on the basis of published scientific articles. Since the very space-time concept has been proved as baseless the question of curvature of space-time being correct does not arise. Gravity has been shown to be an electromagnetic force as foreseen by Maxwell due to the curl/vortices of aether (the electric dipoles) in the published article 'Revised Foundation of Theory of Everything: Non-living Things & Living Things' (www.indjst.org; Sep 2010) Revised version of this article is available on vixra & World Science Database in my profile. Open challenge could seen at http://www.worldsci.org/php/index.php?tab0=Abstracts&tab1=Display&id=6476&tab=2 and http://www.gsjournal.net/Science-Journals/Essays/View/4018 .

    World should force all the physicists of the world to join to accept the standing open challenge (against the foundation of materialism at social, political & scientific level) and produce the rebuttal article to the scientific articles on the basis of which open challenge has been put forward; the very well known & only accepted procedure of denying the scientific findings published in peer-reviewed journals.

    However for the information of all I would like to state here that every concerned physicist of the world is in total knowledge of the open challenge and they also know that they.
    can do nothing about it technically & scientifically. They would have easily accepted the alternative paradigm of physics which emerges as the consequence of my scientific publications but that would reduce their degrees to trash and they will have to quit their jobs on the basis of morality. Besides there is fund flow of trillions of dollars annually for research in thousands of research institutions all over the world and once world comes to know that all these institutions have been knowingly wasting trillions of dollars of public money; then many (millions) heads would have to role.

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