Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

First black holes may have incubated in giant, starlike cocoons

25.11.2009
The first large black holes in the universe likely formed and grew deep inside gigantic, starlike cocoons that smothered their powerful x-ray radiation and prevented surrounding gases from being blown away, says a new study led by the University of Colorado at Boulder.

The formation process involved two stages, said Mitchell Begelman, a professor and the chair of CU-Boulder's astrophysical and planetary sciences department. The predecessors to black hole formation, objects called supermassive stars, probably started forming within the first few hundred million years after the Big Bang some 14 billion years ago.

A supermassive star eventually would have grown to a huge size -- as much as tens of millions of times the mass of our sun -- and would have been short-lived, with its core collapsing in just in few million years, he said.

In the new study to be published in Monthly Notices of the Royal Astronomical Society in London, Begelman calculated how supermassive stars might have formed, as well as the masses of their cores. These calculations allowed him to estimate their subsequent size and evolution, including how they ultimately left behind "seed" black holes.

Begelman said the hydrogen-burning supermassive stars would had to have been stabilized by their own rotation or some other form of energy like magnetic fields or turbulence in order to facilitate the speedy growth of black holes at their centers. "What's new here is we think we have found a new mechanism to form these giant supermassive stars, which gives us a new way of understanding how big black holes may have formed relatively fast," said Begelman.

The main requirement for the formation of supermassive stars is the accumulation of matter at a rate of about one solar mass per year, said Begelman. Because of the tremendous amount of matter consumed by supermassive stars, subsequent seed black holes that formed in their centers may have started out much bigger than ordinary black holes -- which are the mass of only a few Earth suns -- and subsequently grew much faster.

After the seed black holes formed, the process entered its second stage, which Begelman has dubbed the "quasistar" stage. In this phase, black holes grew rapidly by swallowing matter from the bloated envelope of gas surrounding them, which eventually inflated to a size as large as Earth's solar system and cooled at the same time, he said.

Once quasistars cooled past a certain point, radiation began escaping at such a high rate that it caused the gas envelope to disperse and left behind black holes up to 10,000 times or more the mass of Earth's sun, Begelman said. With such a big head start over ordinary black holes, they could have grown into supermassive black holes millions or billions of times the mass of the sun either by gobbling up gas from surrounding galaxies or merging with other black holes in extremely violent galactic collisions.

The quasistar phase was analyzed in a 2008 paper published by Begelman in collaboration with CU Professor Phil Armitage and Research Associate Elena Rossi.

"Until recently, the thinking by many has been that supermassive black holes got their start from the merging of numerous, small black holes in the universe," he said. "This new model of black hole development indicates a possible alternate route to their formation."

Black holes are extremely dense celestial objects believed to be formed by the collapse of stars and which have such a strong gravitational field that nothing, not even light, can escape. While black holes are not directly detectable by astronomers, the movement of stellar matter swirling around them and powerful jets of gas blasting outward provides evidence for their existence. Ordinary black holes are thought to be remnants of stars slightly larger than our sun that used up their fuel and died, he said.

The supermassive black holes created early in the history of the universe may have gone on to produce the phenomenon of quasars -- the very bright, energetic centers of distant galaxies that can be a trillion times brighter than our sun. There also is evidence that a supermassive black hole inhabits the center of every massive galaxy today, including our own Milky Way, said Begelman.

"Big black holes formed via these supermassive stars could have had a huge impact on the evolution of the universe, including galaxy formation," he said. Begelman is collaborating with University of Michigan astrophysicist Marta Volonteri, comparing the possible formation of supermassive black holes from supermassive stars and quasistars versus their creation by the merging of ordinary black holes left behind by the collapse of the universe's earliest stars.

Scientists may be able to use NASA's James Webb Space Telescope, slated for launch in 2013, to look back in time and hunt for the cocoon-like supermassive stars near the edges of the early universe, which would shine brightly in the near infrared portion of the electromagnetic spectrum, said Begelman.

Begelman has authored several books, including "Gravity's Fatal Attraction" with Martin Rees, a member of the British House of Lords and president of the Royal Society of London and who is the British Astronomer Royal, in 1996. The second edition of the book is due out early next year. Begelman also authored "Turn Right at Orion: Travels Through the Cosmos" in 2000.

Mitchell Begelman | EurekAlert!
Further information:
http://www.colorado.edu

More articles from Physics and Astronomy:

nachricht Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>