Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Powerful magnetic fields challenge black holes' pull

05.06.2014

Black holes are thought to dominate their surroundings by their extremely powerful gravitational pull.

However, other forces which are usually considered to be weaker are also at work near these objects. These include forces exerted by the pressure of the in-falling hot gas and magnetic forces.


A computer simulation of gas (in yellow) falling into a black hole (too small to be seen). Twin jets are also shown with magnetic field lines. Credit: Alexander Tchekhovskoy (LBNL)

In a surprising twist, a team of astronomers at the Max Planck Institute for Radio Astronomy (MPIfR) and Lawrence Berkeley National Laboratory (LBNL) has found that in fact magnetic forces can be as strong as gravity near supermassive black holes. These findings are published in this week's issue of Nature.

Some black holes that are voraciously consuming interstellar gas also expel some of it in twin narrow outflows, or jets. This study focused on those supermassive black holes at the centers of galaxies that have observed radio-emitting jets.

"We realized that the radio emission from a black hole's jets can be used to measure the magnetic field strength near the black hole itself", says the study's lead-author, Mohammad Zamaninasab (formerly at the MPIfR and supported by a grant from Deutsche Forschungsgemeinschaft, DFG). "Our real aha experience came when we compared our magnetic force measurements to the force of gravity near black holes, and found them to be comparable”, he continues.

On a purely theoretical level, the possibility that magnetic fields may be as strong as gravity near black holes has been studied by state-of-the-art computer simulations. “When the in-falling gas carries enough magnetic field in our simulations, then the magnetic field near the black hole gets stronger until it balances gravity”, explains Alexander Tchekhovskoy (LBNL), a co-author of the study. “This fundamentally changes the behavior of the gas near the black hole.”

Surprisingly, the magnetic field strength around these exotic objects is comparable to the magnetic field produced in something more familiar: a magnetic resonance imaging (MRI) machine that you can find in your local hospital. Both supermassive black holes and MRI machines produce magnetic fields that are roughly 10 000 times stronger than the Earth's surface magnetic field, which is what guides an ordinary compass.

The measurements of the magnetic field strength near the black hole were based on mapping what fraction of the radio emission is absorbed at different locations near the base of the jet. “Such observations existed for an order of hundred sources from earlier work of several international re-search teams using the Very Long Baseline Array, a network of radio telescopes spread across the United States”, says co-author Tuomas Savolainen from MPIfR. “A large fraction of these measurements had just relatively recently become available thanks to a large observing program called MOJAVE, which monitors several hundred jets launched by supermassive black holes.”

The strength of the magnetic field near the black hole horizon also controls how powerful its jets are and, therefore, how luminous they appear at radio wavelengths according to current theories that treat black holes as a sort of spinning magnet. Thus, it is possible that the bright radio jets emanate from those black hole systems that have magnetic fields as strong as gravity.

These results may lead to changes in how to interpret black hole observations. “If our ideas hold up to further scrutiny, then astronomers' expectations for how to measure black hole properties would need to be changed.” concludes Eric Clausen-Brown, also from MPIfR. “Our study also changes how powerful we expect black hole jets can be, and since these jets can impact their own galaxies and beyond, we may need to rethink how much of an environmental impact black holes can have.”

Original Paper:

Dynamically-important magnetic fields near accreting supermassive black holes, by M. Zamaninasab, E. Clausen-Brown, T. Savolainen, A. Tchekhovskoy, published in: 2014, Nature. DOI: 10.1038/nature13399
http://www.nature.com/nature/journal/v510/n7503/full/nature13399.html
(after the embargo expires).

Contact:

Dr. Mohammad Zamaninasab
Fon: +49(0)176 64972814
E-mail: m.zamaninasab@gmail.com

Dr. Eric Clausen-Brown
Max-Planck-Institut für Radioastronomie.
Fon: +49(0)228-525-473
E-mail: clausenbrown@mpifr-bonn.mpg.de

Dr. Tuomas Savolainen
Max-Planck-Institut für Radioastronomie
Fon: +49(0)228-525-473
E-Mail: tsavolainen@mpifr-bonn.mpg.de

Dr. Norbert Junkes,
Press and Public Outreach,
Max-Planck-Institut für Radioastronomie.
Fon: +49(0)228-525-399
E-mail: njunkes@mpifr-bonn.mpg.de

Weitere Informationen:

http://www.mpifr-bonn.mpg.de/pressreleases/2014/6

Norbert Junkes | Max-Planck-Institut

Further reports about: LBNL MPIfR MRI Max-Planck-Institut Radioastronomie Savolainen galaxies gravity measurements

More articles from Physics and Astronomy:

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

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

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

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>