Quasars May be Powered by Spectacular Galactic Crashes

Using the Hubble Space Telescope's infrared vision, astronomers have unveiled some of the previously hidden origins of quasars, the brightest objects in the universe. It turns out that these quasars are born when galaxies crash into each other and fuel supermassive, central black holes.

"The Hubble images confirm that the most luminous quasars in the universe result from violent mergers between galaxies, which fuels black hole growth and transforms the host galaxies," said C. Megan Urry, co-author of the new study, in a news release. "These mergers are also the sites of future black hole mergers, which we hope will one day be visible with gravitational wave telescopes."

Quasars emit a light that's as bright as that of one trillion stars. Over the past two decades, researchers have concluded that the energy for quasars comes from supermassive black holes inside the cores of distant galaxies.

But where do black holes get their fuel? Previously, scientists theorized that the energy could come from the merger of two galaxies. This new study, though, confirms this theory by using Hubble's sensitivity at near-infrared wavelengths of light to see past the intense glow of the quasar to the host galaxies themselves.

"The Hubble observations are telling us that the peak of quasar activity in the early universe is driven by galaxies colliding and then merging together," said Eilat Glikman, lead author of the new study. "We are seeing the quasars in their teenage years, when they are growing quickly and all messed up."

The researchers looked at quasars enveloped in dust from the peak of the universe's star-formation era, about 12 billion years ago. The new images actually capture the dust-clearing transitional phase of the merger-driven black hole scenario.

The findings reveal a bit more about black holes and the role that quasars play with them.

The findings are published in The Astrophysical Journal.

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