Astronomers find link between supermassive black holes and galaxy formation

February 3rd, 2009 - 1:38 pm ICT by ANI  

Washington, Feb 3 (ANI): A team of astronomers has uncovered new evidence that points to a link between supermassive black holes and galaxy formation.

The astronomers, from Texas and Germany, used a telescope at The University of Texas at Austins McDonald Observatory, together with the Hubble Space Telescope and many other telescopes around the world to discover that the largest, most massive galaxies in the universe and the gigantic black holes at their hearts grew together over time.

Astronomers know that galaxies, which are vast cities of millions or billions of stars, grow larger through collisions and mergers.

The work of University of Texas at Austins John Kormendy, and Ralf Bender of Germanys Max-Planck-Institute for Extraterrestrial Physics, involves the biggest galaxies in the universe called elliptical galaxies that are shaped roughly like footballs and that can be made of as many as a thousand billion stars.

Virtually, all of these galaxies contain a black hole at their centers, that is, an infinitely dense region that contains the mass of millions or billions of Suns and from which no light can escape.

Our new observations are a strong and direct link between black holes and galaxy central properties, Kormendy said. They are a smoking gun that connects black holes with the formation of the surprisingly fluffy centers of giant elliptical galaxies, he added.

Kormendy and Bender made detailed studies of 11 such galaxies in the Virgo Cluster.

To get a comprehensive overall picture of each galaxy, they used the wide field of view of the Prime Focus Camera on McDonald Observatorys 0.8-meter Telescope.

They used Hubble Space Telescope to study these same galaxies cores in great detail.

Many other telescopes were used to connect the central data from Hubble with the outer data from the McDonald telescope.

Their precision measurements of the brightnesses - that is, the number of stars - at various distances from the centers of elliptical galaxies allowed them to calculate much more accurately than previously the masses of stars that are missing in the centers of the biggest ellipticals.

It was found that the missing mass increases in lockstep with the measured masses of the central black holes.

The missing mass also increases in lockstep with another galaxy property that is known to be tied directly to black holes, namely the speeds at which stars move far out in the galaxy where they cannot feel the black holes gravity.

According to Bender, The new observations give us much stronger evidence that black holes control galaxy formation, at least at their centers. (ANI)

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