Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

"Survivor" Black Holes May Be Mid-Sized

30.04.2010
New evidence from NASA's Chandra X-ray Observatory and ESA's XMM-Newton strengthens the case that two mid-sized black holes exist close to the center of a nearby starburst galaxy. These "survivor" black holes avoided falling into the center of the galaxy and could be examples of the seeds required for the growth of supermassive black holes in galaxies, including the one in the Milky Way.

For several decades, scientists have had strong evidence for two distinct classes of black hole: the stellar-mass variety with masses about ten times that of the Sun, and the supermassive ones, located at the center of galaxies, that range from hundreds of thousands to billions of solar masses.

But a mystery has remained: what about black holes that are in between?

Evidence for these objects has remained controversial, and until now there were no strong claims of more than one such black hole in a single galaxy. Recently, a team of researchers has found signatures in X-ray data of two mid-sized black holes in the starburst galaxy M82 located 12 million light years from Earth.

"This is the first time that good evidence for two mid-sized black holes has been found in one galaxy," said Hua Feng of the Tsinghua University in China, who led two papers describing the results. "Their location near the center of the galaxy might provide clues about the origin of the Universe's largest black holes – supermassive black holes found in the centers of most galaxies."

One possible mechanism for the formation of supermassive black holes involves a chain reaction of collisions of stars in compact star clusters that results in the buildup of extremely massive stars, which then collapse to form intermediate-mass black holes. The star clusters then sink to the center of the galaxy, where the intermediate-mass black holes merge to form a supermassive black hole.

In this picture, clusters that were not massive enough or close enough to the center of the galaxy to fall in would survive, as would any black holes they contain.

"We can't say whether this process actually occurred in M82, but we do know that both of these possible mid-sized black holes are located in or near star clusters," said Phil Kaaret from the University of Iowa, who co-authored both papers. "Also, M82 is the nearest place to us where the conditions are similar to those in the early Universe, with lots of stars forming."

The evidence for these two "survivor" black holes comes from how their X-ray emission varies over time and analysis of their X-ray brightness and spectra, i.e., the distribution of X-rays with energy.

Chandra and XMM-Newton data show that the X-ray emission for one of these objects changes in a distinctive manner similar to stellar-mass black holes found in the Milky Way. Using this information and theoretical models, the team estimated this black hole's mass is between 12,000 and 43,000 times the mass of the Sun. This mass is large enough for the black hole to generate copious X-rays by pulling gas directly from its surroundings, rather than from a binary companion, like with stellar-mass black holes.

The black hole is located at a projected distance of 290 light years from the center of M82. The authors estimate that, at this close distance, if the black hole was born at the same time as the galaxy and its mass was more than about 30,000 solar masses it would have been pulled into the center of the galaxy. That is, it may have just escaped falling into the supermassive black hole that is presumably located in the center of M82.

The second object, located 600 light years in projection away from the center of M82, was observed by both Chandra and XMM-Newton. During X-ray outbursts, periodic and random variations normally present in the X-ray emission disappear, a strong indication that a disk of hot gas dominates the X-ray emission. A detailed fit of the X-ray data indicates that the disk extends all the way to the innermost stable orbit around the black hole. Similar behavior has been seen from stellar-mass black holes in our Galaxy, but this is the first likely detection in a candidate intermediate-mass black hole.

People Who Read This Also Read...
Milky Way's Super-efficient Particle Accelerators Caught in The Act
Black Holes Are The Rhythm at The Heart of Galaxies
Black Holes Have Simple Feeding Habits
NASA Unveils Cosmic Images Book in Braille for Blind Readers
The radius of the innermost stable orbit depends only on the mass and spin of the black hole. The best model for the X-ray emission implies a rapidly spinning black hole with mass in the range 200 to 800 times the mass of the Sun. The mass agrees with theoretical estimates for a black hole created in a star cluster by runaway collisions of stars.

"This result is one of the strongest pieces of evidence to date for the existence of an intermediate-mass black hole," said Feng. "This looks just like well-studied examples of stellar-mass black holes, except for being more than 20 times as massive."

The two papers describing these results recently appeared in The Astrophysical Journal. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

The XMM-Newton spacecraft is controlled by the European Space Operations Center. The XMM-Newton Science Operations Center situated at ESAC in Villafranca, Spain, manages observation requests and receives XMM-Newton data. The XMM-Newton Survey Science Centre at Leicester University, UK, processes and correlates all XMM-Newton observations with existing sky data held elsewhere in the world.

More information, including images and other multimedia, can be found at:

http://chandra.harvard.edu and http://chandra.nasa.gov and http://www.esa.int/esaSC/
Media contacts:
Norbert Schartel
ESA ESAC
+34 91 8131 184
Norbert.Schartel@esa.int
Janet Anderson
NASA Marshall Space Flight Center, Ala.
256-544-6162
janet.l.anderson@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
http://chandra.harvard.edu/press/10_releases/press_042910.html

More articles from Physics and Astronomy:

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>