HEAPOW: Blowing Bubbles (2019 Apr 08)
One of the most surprising science results of the Fermi Gamma-ray Space Telescope was the discovery of two enormous, gamma-ray emitting, bubble-like structures extending more than 25,000 light years above and below the center of our Milky Way galaxy. The origin of these "Fermi Bubbles" is still not fully clear, but they were probably formed millions of years ago by a giant outburst by our own beloved supermassive black hole, Sgr A*. Such an outburst could have been produced by some enormous quantity of matter falling into the black hole, forming a massive accretion disk along with powerful, transient jets of the types associated with central supermassive black holes in other galaxies. These jets could have blasted their way out of the Galaxy and into intergalactic space, forming the bubbles. The high-energy gamma-ray glow they emit is produced by charged particles accelerated to nearly the speed of light inside the bubbles. Now a new X-ray map of the area near the center of the Milky Way near the base of the Fermi Bubbles and Sgr A* by the XMM-Newton X-ray observatory has revealed collimated outflows of hot, X-ray emitting gas from the vicinity of Sgr A* extending for hundreds of light years into the Fermi Bubbles. The image above shows XMM-Newton's X-ray color map of this region, where red represents the total emission in the low-energy band, while green represents emission primarily from ionized atoms of sulfur, and blue higher energy emission. (White spots show regions where emission from individual sources have been removed to reveal the diffuse X-ray glow from the outflow.) The analysis of these XMM-Newton data suggest a powerful flow of hot gas from the center of the Milky Way along two channels which feed the base of the Fermi Bubbles, like hot air flowing through a chimney. These chimneys may have been produced by episodic outbursts from Sgr A* which help keep the Fermi Bubbles inflated.
XMM-Newton: Giant 'Chimneys' Vent X-rays from Milky Way's Core
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