Saturday, July 28, 2007

Another Dark ... Matter

Addendum 2/16/2010:


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Well again I am looking at Dark Matter. Well not exactly looking at it.




Here is a picture of NGC 4254. It is a beautiful spiral galaxy in the Virgo cluster. Notice its arm is pulled away from the galaxy. This is a question that has perplexed astronomers for years. Now it is understood.

The radio telescope of Arecibo Observatory, Cardiff University, Isaac Newton Telescope, and Westerbork Synthesis Radio Telescope have found a gas cloud of neutral Hydrogen and dark matter nearby. The finding of this cloud goes along way to understanding NGC 4254's outstretched arm.




Here is a picture of the area in the Virgo Cluster called VIRGOHI 21. Notice that the area is not visible. This is a Dark Matter Galaxy.


When we look at the area in the 21cm wavelength we see hydrogen gas jetting from NGC 4254 to VIRGOHI 21. In the third picture the Neutral hydrogen gas streams between NGC 4254 (top left) and the Dark Galaxy VIRGOHI 21 (center right) in this image made from radio telescope observations at a wavelength of 21 centimetres. This interaction could explain the mystery of NGC 4254's peculiar lopsided shape. To the bottom left, a ring of gas can be seen around the galaxy NGC 4262. This material was presented to the American Astronomical Society meeting in Washington, D. C. on January 12, 2006.

Even though Neutral Hydrogen is detected streaming into VIRGOHI 21, there is not enough hydrogen to cause the extension of the arm in NGC 4254. Something dense but dark is necessary to explain this. This is an example of Dark Matter.

Aaron

CREDIT: Arecibo Observatory / Cardiff University / Westerbork Synthesis Radio Telescope.
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