Image of the Day: “Galactic Magic”



This image shows central region of the spiral galaxy NGC 4631, "The Whale," as seen edge-on from NASA's Chandra X-ray Observatory and Hubble Space Telescope. The Chandra data (shown in blue and purple) provide the first unambiguous evidence for a halo of hot gas surrounding a galaxy that is very similar to our Milky Way. 

The structure across the middle of the image and the extended faint filaments (shown in orange) represent the observation from Hubble that reveals giant bursting bubbles created by clusters of massive stars. Scientists have debated for over 40 years whether the Milky Way has an extended corona, or halo, of hot gas. Observations of NGC 4631 and similar galaxies provide astronomers with an important tool in the understanding our own galactic environment.

The most massive stars that form in star formation regions only burn hydrogen gas through fusion for a short period of time, after which they explode as supernovae. The many supernovae that have exploded in the central region, that they are blowing gas out of the galactic plane creating superwinds can be seen in X-rays and inspectral line emission.The gas from this superwind has produced a giant, diffuse corona of hot, X-ray emitting gas around the entire galaxy.

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