Observations help pinpoint why old, giant galaxies stop forming stars
BOSTON — A monster galaxy dating to the universe’s first 2 billion years may fill in a missing chapter in the story of galactic evolution. Shut down by a supermassive black hole, the galaxy appears to have wrapped up an intense burst of star formation and begun regurgitating its star-building fuel. The finding may help astronomers connect prolific galaxies in the very early universe with the silent giants seen today.
Cemile Marsan, an astrophysicist at Tufts University in Medford, Mass., observed the galaxy using ultraviolet, visible and infrared wavelengths of light. Before its death, the galaxy built up a mass of roughly 300 billion suns in less than 500 million years.
At a June 4 press conference at the American Astronomical Society meeting, Marsan said a supermassive black hole at the core of the galaxy is robbing the galaxy of material for making stars. What doesn’t get sucked down the black hole’s throat gets spat into intergalactic space, far from the galaxy’s grasp.
The observations support the idea that a supermassive black hole can control the fate of an entire galaxy despite being minuscule in comparison.
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Z.C. Marsan et al. Spectroscopic confirmation of an ultra massive and compact galaxy at z=3.35: a detailed look at an early progenitor of local most massive ellipticals. arXiv:1406.0002. Posted June 2, 2014.