Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Astronomers discover link between supermassive black holes and galaxy formation

A pair of astronomers from Texas and Germany have used a telescope at The University of Texas at Austin's McDonald Observatory together with Hubble Space Telescope and many other telescopes around the world to uncover new evidence that the largest, most massive galaxies in the universe and the supermassive black holes at their hearts grew together over time.

"They evolved in lockstep," said The University of Texas at Austin's John Kormendy, who co-authored the research with Ralf Bender of Germany's Max-Planck-Institute for Extraterrestrial Physics and Ludwig Maximilians University Observatory. The results are puiblished in this week's issue of Astrophysical Journal Letters.

Astronomers know that galaxies, those vast cities of millions or billions of stars, grow larger through collisions and mergers. Kormendy and Bender's work involves the biggest galaxies in the universe--"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.

A current leading theory says that when galaxies collide, their black holes end up revolving around each other. Together, the two black holes act like an egg beater: They violently stir up the galaxy center with their incredibly strong gravity, and they fling stars out of the central regions. As the black hole pair sinks to the center of the new merger remnant, this supergalaxy's core is depleted of the stars that were flung away. Kormendy and Bender measured the resulting dimming of such galaxies' cores, their so-called "light deficits."

Light deficits in galaxy cores are surprising in view of decades of work by many astronomers, including Kormendy and Bender, which showed that the biggest elliptical galaxies contain the most massive black holes at their centers. These are monsters "weighing in" at a billion or more times the mass of our Sun. They attract the stars around them with ferociously strong gravity. Astronomers expected that such big black hole would yank the galaxy's stars into a tiny, dense cluster at the center. But observations in the 1980s with ground-based telescopes and much better observations in the 1990s with Hubble Space Telescope revealed the opposite. The biggest galaxies have big, fluffy, low-density centers. Why are giant black holes not surrounded by dense cluster of stars? Where did the missing stars go?

The theory that black hole binaries gravitationally slingshot the stars out of galactic centers has been the popular but unproved explanation. No telescope observations provided compelling evidence--until now.

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

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 Observatory's 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. The results on 27 elliptical galaxies in the Virgo Cluster measured by Kormendy, Bender, and their University of Texas colleagues David Fisher and Mark Cornell, and supported by the National Science Foundation, are scheduled for publication in a forthcoming issue of the Astrophysical Journal Supplement Series.

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. This revealed more surprises: The missing mass increases in lockstep with the measured masses of the central black holes. It was known that the two quantities are related, but it was not known that the correlation is so tight as to be within the margin of error. That is, the correlation is virtually perfect.

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 hole's gravity.

"Astronomers love tight correlations," Bender says. "They tell us what is connected with what. The new observations give us much stronger evidence that black holes control galaxy formation, at least at their centers."

According to Linda Sparke, NSF program director for astronomical sciences, "This valuable research shows how black holes grow along with the galaxy. This is big news. We've long accepted that black holes are not scattered randomly in galaxies. The most luminous galaxies harbor the most massive black holes. But we haven't known just how the black hole and the galaxy influence each other. Kormendy and Bender have seen the footprint of merging pairs of black holes in the centers of huge elliptical galaxies, revealing evidence that the largest black holes form after smaller galaxies collide to produce one larger system."

Kormendy finally adds, "We have long believed that black holes power quasars in galactic nuclei--they are the brightest objects in the universe. And we have come to suspect that putting giant black holes at the centers of young galaxies and shining so much quasar light on them affects galaxy formation. In other words, we suspect that the study of quasars and the study of galaxies are really one subject. We can't understand one without understanding the other.

"We think we have helped to merge these subjects by connecting black holes directly to galaxy structure." he said. "John Muir famously said that everything is hitched to everything else in the world. As we find that different subjects are hitched together, we build a theory of galaxy formation that we confidently believe."

Lisa-Joy Zgorski | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>