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New Evidence That Supermassive Black Holes Eventually Suck the Life out of Big Galaxies

New Evidence That Supermassive Black Holes Eventually Suck the Life out of Big Galaxies
From Gizmodo - January 2, 2018

At the core of each large galaxy lies a supermassive black hole with the mass of 1 million suns. New research shows that these celestial vacuum cleaners do more than just devour nearby objectsthey also grow to a size that eventually suppresses a galaxys ability to churn out new stars, effectively rendering them sterile.

Young galaxies are absolutely bursting with bright, newly formed stars. As time passes, however, star formation eventually grinds to a halt. A new study published in Nature shows that supermassive black holes play a critical role in determining when large galaxies stop producing new stars, a process known as quenching.

Stars form out of cold gas, so when a galaxy runs out of cold gas its effectively quenched. One possible way this could happenat least for galaxies with supermassive black holesis that the gas that pours onto a supermassive black hole triggers the production of high-energy jets. The energy released by these jets can expel cold gas out of the galaxy, causing star formation to shut down.

At least thats the theory. This idea has been around for quite some time, but no observational evidence existed to support the alleged correlation between supermassive black holes and star formation. The new study, led by Ignacio Martn-Navarro from the University of California Santa Cruz, now fills this gap in our knowledge.

Using data collected by the Hobby-Eberly Telescope Massive Galaxy Survey, Martn-Navarros team analyzed the spectra of light coming from distant galaxies. This allowed them to separate and measure the varying wavelengths of light coming from these distant objects. The scientists used this data to create a historical snapshot of a galaxys star formation history. They then compared this history with black holes of different masses, which resulted in some striking differencesdifferences that correlated with black hole mass, but not the shape, size, or other properties of black holes.

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