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Saturday, November 5, 2011

Hubble directly observes the Disc around a Black Hole!

Hubble directly observes the Disc around a Black Hole!
Click on the image for full resolution

A team of scientists has used the NASA/ESA Hubble Space Telescope to observe a quasar accretion disc - a brightly glowing disc of matter that is slowly being sucked into its galaxy's central black hole. Their study makes use of a novel technique that uses gravitational lensing to give an immense boost to the power of the telescope. The incredible precision of the method has allowed astronomers to directly measure the disc's size and plot the temperature across different parts of the disc. This picture shows the quasar HE 1104-1805 that has been gravitationally lensed by a galaxy in the foreground, which can be seen as a faint shape around the two bright images of the quasar. Observations of one of the images show variations in colour over time. This is caused by stars within the lens galaxy passing through the path of the light from the quasar, magnifying the light from different parts of the quasar's accretion disc as they move. This has allowed a team of scientists to reconstruct the colour and temperature profile of the accretion disc with unprecedented precision. The level of detail involved is equivalent to being able to study individual grains of sand on the surface of the Moon while standing on Earth.
Credit: NASA, ESA and J.A. Muñoz (University of Valencia)

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