A Voracious Galaxy?
What's going on with 3c297? The galaxy 3c297, about 9 billion light-years from earth, seems at first glance to be just another active galaxy with an actively accreting supermassive black hole near the center. But multi-wavelength images of 3C297 show that it has some unusal propoerties: a large reservoir of million-degree plasma surrounds the galaxy and glows in X-rays (as seen by the Chandra X-ray Observatory, shown in purple in the image above); a radio jet (seen by the Karl G. Jansky Very Large Array, and shown in red, emanating from the center of the image and sweeping down towards the lower right corner) originating from a supermassive black hole near the center of the galaxy (the white spot near the center of the image), which has been re-directed by interacting with gas in its vicinity; and another radio jet (from the central black hole pointing towards the upper right) ending in an X-ray bright "hotspot" produced when the jet slammed into circumgalactic matter. These features are unusual for a single galaxy and are typically only seen within clusters of hundreds or thousands of galaxies. But deep optical imaging around 3c297 by the Gemini Observatory did not reveal any other obvious cluster galaxies. So 3c297 seems to be relatively isolated, without any nearby neighbors. What's going on? One interesting explanation involves mergers of galaxies in clusters. Mergers are quite common in clusters, since the galaxies are relatively close together. It may be that 3c297 is a fossil galaxy left behind after it ate all the galaxies in a former cluster, leaving behind the large halo of hot matter around 3c297 seen in the Chandra X-ray images and the actively-feeding supermassive black hole at its center.
CXC: Astronomers Discover a Surprisingly Lonely Galaxy (3C 297)
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