Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Black Hole Growth Found to be Out of Synch

13.06.2012
New evidence from NASA's Chandra X-ray Observatory challenges prevailing ideas about how supermassive black holes grow in the centers of galaxies.

Astronomers long have thought that a supermassive black hole and the bulge of stars at the center of its host galaxy grow at the same rate -- the bigger the bulge, the bigger the black hole. A new study of Chandra data has revealed two nearby galaxies whose supermassive black holes are growing faster than the galaxies themselves.


Credit: X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF

The mass of a giant black hole at the center of a galaxy typically is a tiny fraction (about 0.2 percent) of the mass contained in the bulge, or region of densely packed stars, surrounding it. The targets of the latest Chandra study, galaxies NGC 4342 and NGC 4291, have black holes that are 10 times to 35 times more massive than they should be compared to their bulges. The new observations with Chandra show that the halos, or massive envelopes of dark matter in which these galaxies reside, also are overweight.

The new study suggests the two supermassive black holes and their evolution are tied to their dark matter halos and they did not grow in tandem with the galactic bulges. In this view, the black holes and dark matter halos are not overweight, but the total mass in the galaxies is too low.

"This gives us more evidence of a link between two of the most mysterious and darkest phenomena in astrophysics -- black holes and dark matter -- in these galaxies," said Akos Bogdan of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass, who led the new study.

NGC 4342 and NGC 4291 are close to Earth in cosmic terms, at distances of 75 million and 85 million light years, respectively. Astronomers had known from previous observations that these galaxies host black holes with relatively large masses, but astronomers are not certain what is responsible for the disparity. Based on the new Chandra observations, however, they are able to rule out a phenomenon known as tidal stripping.

Tidal stripping occurs when some of a galaxy's stars are stripped away by gravity during a close encounter with another galaxy. If such tidal stripping had taken place, the halos also mostly would have been missing. Because dark matter extends farther away from the galaxies, it is more loosely tied to them than the stars and is more likely to be pulled away.

To rule out tidal stripping, astronomers used Chandra to look for evidence of hot, X-ray emitting gas around the two galaxies. Because the pressure of hot gas – estimated from X-ray images -- balances the gravitational pull of all the matter in the galaxy, the new Chandra data can provide information about the dark matter halos. The hot gas was found to be widely distributed around both NGC 4342 and NGC 4291, implying that each galaxy has an unusually massive dark matter halo, and therefore that that tidal stripping is unlikely.

"This is the clearest evidence we have, in the nearby universe, for black holes growing faster than their host galaxy," said co-author Bill Forman, also of CfA. "It's not that the galaxies have been compromised by close encounters, but instead they had some sort of arrested development."

How can the mass of a black hole grow faster than the stellar mass of its host galaxy? The study's authors suggest that a large concentration of gas spinning slowly in the galactic center is what the black hole consumes very early in its history. It grows quickly, and as it grows, the amount of gas it can accrete, or swallow, increases along with the energy output from the accretion. Once the black hole reaches a critical mass, outbursts powered by the continued consumption of gas prevent cooling and limits the production of new stars.

"It's possible that the supermassive black hole reached a hefty size before there were many stars at all in the galaxy," said Bogdan. "That is a significant change in our way of thinking about how galaxies and black holes evolve together."

These results were presented June 11 at the 220th meeting of the American Astronomical Society in Anchorage, Alaska. The study also has been accepted for publication in The Astrophysical Journal.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for the agency's NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra's science and flight operations.

For Chandra images, multimedia and related materials, visit:
http://www.nasa.gov/chandra
For an additional interactive image, podcast, and video on the finding, visit:
http://chandra.si.edu
Media contacts:
J.D. Harrington
Headquarters, Washington
202-358-0321
j.d.harrington@nasa.gov
Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu

Megan Watzke | EurekAlert!
Further information:
http://www.cfa.harvard.edu

More articles from Physics and Astronomy:

nachricht Immortal quantum particles: the cycle of decay and rebirth
14.06.2019 | Technische Universität München

nachricht Small currents for big gains in spintronics
13.06.2019 | University of Tokyo

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: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

Im Focus: Cost-effective and individualized advanced electronic packaging in small batches now available

Fraunhofer IZM is joining the EUROPRACTICE IC Service platform. Together, the partners are making fan-out wafer level packaging (FOWLP) for electronic devices available and affordable even in small batches – and thus of interest to research institutes, universities, and SMEs. Costs can be significantly reduced by up to ten customers implementing individual fan-out wafer level packaging for their ICs or other components on a multi-project wafer. The target group includes any organization that does not produce in large quantities, but requires prototypes.

Research always means trying things out and daring to do new things. Research institutes, universities, and SMEs do not produce in large batches, but rather...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Concert of magnetic moments

14.06.2019 | Information Technology

Materials informatics reveals new class of super-hard alloys

14.06.2019 | Materials Sciences

New imaging modality targets cholesterol in arterial plaque

14.06.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>