[/caption] Can you imagine living in this region of space? Just think of the beautiful views you'd have in the sky – that is, if you survived the chaos as one galaxy is passing through the core of three other galaxies at ridiculous (ludicrous?) speeds (3.2 million km per hour / 2 million miles per hour) generating a shock wave of gas and X-rays.
This is Stephen's Quintet, A compact group of galaxies, discovered about 130 years ago, located about 280 million light years from Earth. The curved, light blue ridge running down the center of the image shows X-ray data from the Chandra X-ray Observatory. The galaxy in the middle, NGC 7318b is passing through the core of the other galaxies at high speed and is thought to be causing the ridge of X-ray emission by generating a shock wave that heats the gas. The most prominent galaxy in front (NGC 7320) is actually far away from the other galaxies and is not part of the group.
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See the Chandra webpage for a roll-over labeled version
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Additional heating by supernova explosions and stellar winds has also probably taken place in Stephan's Quintet. A larger halo of X-ray emission - not shown here - detected by ESA's XMM-Newton could be evidence of shock-heating by previous collisions between galaxies in this group. Some of the X-ray emission is likely also caused by binary systems containing massive stars that are losing material to neutron stars or black holes.
Stephan's Quintet provides a rare opportunity to observe a galaxy group in the process of evolving from an X-ray faint system dominated by spiral galaxies to a more developed system dominated by elliptical galaxies and bright X-ray emission. Being able to witness the dramatic effect of collisions in causing this evolution is important for increasing our understanding of the origins of the hot, X-ray bright halos of gas in groups of galaxies.
Source:
Chandra