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Originally Posted by Royal Astronomical Society Press Release 14 Aug 2015
A spectacular galaxy collision has been discovered lurking behind the Milky Way. The closest such system ever found, the discovery was announced today by a team of astronomers led by Prof. Quentin Parker at the University of Hong-Kong and Prof. Albert Zijlstra at the University of Manchester. The scientists publish their results in Monthly Notices of the Royal Astronomical Society.
The galaxy is 30 million light years away, which means that it is relatively close by. It has been dubbed “Kathryn’s Wheel” both after the famous firework that it resembles, but also after the wife of the paper's second author.
Such systems are very rare and arise from “bulls-eye” collisions between two galaxies of similar mass. Shockwaves from the collision compress reservoirs of gas in each galaxy and trigger the formation of new stars. This creates a spectacular ring of intense emission, and lights up the system like a Catherine wheel firework on bonfire night.
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Kathryn's Wheel was discovered during a special wide field survey of the Southern Milky Way undertaken with the UK Schmidt Telescope in Australia.
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The newly discovered ring galaxy is seven times closer than anything similar found before, and forty times closer than the famous ‘Cartwheel’ galaxy. The ring is located behind a dense star field and close to a very bright foreground star, which is why it had not been noted before. There are very few other galaxies in its neighbourhood; the odds of a collision in such an empty region of space are very low.
Professor Parker said “Not only is this system visually stunning, but it’s close enough to be an ideal target for detailed study. The ring is also quite low in mass – a few thousand million Suns, or less than 1% of the Milky Way – so our discovery shows that collision rings can form around much smaller galaxies than we thought.”
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Press release here -
https://www.ras.org.uk/news-and-pres...laxy-collision
Paper here entitled "Kathryn’s Wheel: a spectacular galaxy collision discovered in the Galactic neighbourhood" -
http://mnras.oxfordjournals.org/cont....full.pdf+html
