• Using radio telescopes, researchers scrutinized four elliptical galaxies apparently on the cusp of changing from groups filled with new stars to ones that had very few. These galaxies lie between 275 million and 375 million light-years from Earth. All appear to have recently shed the vast volumes of gas needed to trigger the formation of new stars, but why that happened isn’t clear, the researchers say.
  • The gas probably wasn’t stripped away by interactions with other galaxies, because the star groups are relatively isolated in space. In the case of a galaxy dubbed J0836, a large mass of cold hydrogen gas near the galaxy may have been blown out of its former home by a supermassive black hole at the center of the galaxy.
  • That cloud lies along a path of material that radiates strongly in radio wavelengths, a sign that the cloud may have been expelled from its parent galaxy at a time when its central black hole was much more active than it is now.

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