Chandra and XMM-Newton provide direct measurement of distant black hole's spin

Mar 05, 2014
Multiple images of a distant quasar known as RX J1131-1231 are visible in this combined view from Chandra (pink) and Hubble (red, green, and blue). Credit: NASA/CXC/Univ of Michigan/R.C.Reis et al; Optical: NASA/STSc

(Phys.org) —Astronomers have used NASA's Chandra X-ray Observatory and the European Space Agency's (ESA's) XMM-Newton to show a supermassive black hole six billion light years from Earth is spinning extremely rapidly. This first direct measurement of the spin of such a distant black hole is an important advance for understanding how black holes grow over time.

Black holes are defined by just two simple characteristics: mass and spin. While astronomers have long been able to measure black hole masses very effectively, determining their spins has been much more difficult.

In the past decade, astronomers have devised ways of estimating spins for black holes at distances greater than several billion light-years away, meaning we see the region around black holes as they were billions of years ago. However, determining the spins of these remote black holes involves several steps that rely on one another.

"We want to be able to cut out the middle man, so to speak, of determining the spins of black holes across the universe," said Rubens Reis of the University of Michigan in Ann Arbor, who led a paper describing this result that was published online Wednesday in the journal Nature.

Reis and his colleagues determined the spin of the supermassive black hole that is pulling in surrounding gas, producing an extremely luminous quasar known as RX J1131-1231 (RX J1131 for short). Because of fortuitous alignment, the distortion of space-time by the gravitational field of a giant elliptical galaxy along the line of sight to the quasar acts as a gravitational lens that magnifies the light from the quasar. Gravitational lensing, first predicted by Einstein, offers a rare opportunity to study the innermost region in distant quasars by acting as a natural telescope and magnifying the light from these sources.

"Because of this gravitational lens, we were able to get very detailed information on the X-ray spectrum – that is, the amount of X-rays seen at different energies – from RX J1131," said co-author Mark Reynolds also of Michigan. "This in turn allowed us to get a very accurate value for how fast the black hole is spinning."

The X-rays are produced when a swirling accretion disk of gas and dust that surrounds the black hole creates a multimillion-degree cloud, or corona near the black hole. X-rays from this corona reflect off the inner edge of the accretion disk. The strong gravitational forces near the black hole alter the reflected X-ray spectrum. The larger the change in the spectrum, the closer the inner edge of the disk must be to the black hole.

"We estimate that the X-rays are coming from a region in the disk located only about three times the radius of the event horizon, the point of no return for infalling matter," said Jon M. Miller of Michigan, another author on the paper. "The black hole must be spinning extremely rapidly to allow a disk to survive at such a small radius."

For example, a spinning black hole drags space around with it and allows matter to orbit closer to the black hole than is possible for a non-spinning black hole.

By measuring the spin of distant black holes researchers discover important clues about how these objects grow over time. If black holes grow mainly from collisions and mergers between galaxies, they should accumulate material in a stable disk, and the steady supply of new material from the disk should lead to rapidly spinning black holes. In contrast, if black holes grow through many small accretion episodes, they will accumulate material from random directions. Like a merry go round that is pushed both backwards and forwards, this would make the black hole spin more slowly.

The discovery that the black hole in RX J1131 is spinning at over half the speed of light suggests this black hole, observed at a distance of six billion light years, corresponding to an age about 7.7 billion years after the Big Bang, has grown via mergers, rather than pulling material in from different directions.

The ability to measure black hole spin over a large range of cosmic time should make it possible to directly study whether the black hole evolves at about the same rate as its host galaxy. The measurement of the spin of the RX J1131-1231 black hole is a major step along that path and demonstrates a technique for assembling a sample of distant with current X-ray observatories.

Prior to the announcement of this work, the most distant with direct spin estimates were located 2.5 billion and 4.7 billion light-years away.

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 in Cambridge, Mass., controls Chandra's science and flight operations.

Explore further: How fast do black holes spin?

More information: Paper: dx.doi.org/10.1038/nature13031

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antialias_physorg
5 / 5 (5) Mar 06, 2014
Black holes are defined by just two simple characteristics: mass and spin.

Wasn't it mass, spin and charge? Though I've always wondered about the latter one, as the mediating entity for that is subject to c (and cannot escape the black hole)...so how would the charge of a black hole affect anything outside? I.e.: how would a charged black hole appear different from an uncharged one?
The discovery that the black hole in RX J1131 is spinning at over half the speed of light

Woha. Mind. Blown.
CaptainCosmic
5 / 5 (2) Mar 06, 2014
AAP: You are correct: mass (M), spin or angular momentum (J), & electric charge (Q) are the only attributes that determine a black hole. In the 1970's Misner, Thorne & Wheeler offered up the "No Hair" theorem to describe BH's. This means that of all the physical properties of the matter that becomes a BH, only M,J,Q remain to external observers. From a practical standpoint most BH's will be electrically neutral since the infalling matter is usually equal in positive & negative charges.

Technically, these bodies of axially-symmetric, charged, rotating mass are governed by the Kerr–Newman metric of General Relativity combined with Maxwell's equations.

Charles
Fleetfoot
5 / 5 (4) Mar 06, 2014
In theory, they could be charged but in practice the surrounding material is neutral and ionised so Coulomb force will encourage the opposite charge to fall from the inner edge of the disc in very slight preference to the same charge hence the BH will tend towards neutral.
no fate
2 / 5 (2) Mar 06, 2014
Neutral....and ionized?
cantdrive85
1 / 5 (4) Mar 06, 2014
Neutral....and ionized?


Is there any wonder the confusion of plasma by most? Most don't know a plasma from the hole in their head...
GSwift7
5 / 5 (4) Mar 06, 2014
Most don't know a plasma from the hole in their head...


My ironometer must be broken; it's reading 110%.

so how would the charge of a black hole affect anything outside?


I wonder about this as well. Magnetism is a result of a moving electric field (or something moving though an electric field), so how can you account for this outside the EH? They claim that the magnetic field of a black hole extends outside the EH.
antialias_physorg
5 / 5 (3) Mar 06, 2014
Neutral....and ionized?

What is so complicated about that? Ionize a cloud of hydrogen atoms. You now have a load of free protons and a free electrons - but the charge integral over the entire cloud is still zero.

so how can you account for this outside the EH? They claim that the magnetic field of a black hole extends outside the EH.

I'll throw out a knee-jerk theory here: Some material outside the EH is ionized (but in sum neutral). While positive and negative parts fall in at the same rate they have different cross sections concerning radiation pressure from stuff that is right at the event horizon (emitting gamma radiation). So you'll get an equilibrium situation at an uneven distribution of charges circling the event horizon (i.e. a net positively or negatively charged accertion disc). Such a circling current creates a magnetic field.

Dunno...could be an entirely different mechanism.
GSwift7
5 / 5 (1) Mar 06, 2014
Dunno...could be an entirely different mechanism


Yeah, everything I can find (from credible sources) seems to be saying that the core material of the black hole itself is casting a magnetic field through the EH as though it's not even there. That just doesn't make sense to me.

We know that distorted spacetime affects EM fields and waves. So how does the electric/magnetic field extend out of the EH when no other EM can? I'm at a complete loss on this one.

I totally understand how the accretion disk spinning around the BH could generate a field around the BH, but I'm at a loss as to how anything EM can cross from inside the EH. Maybe I'm just reading it wrong?
GSwift7
5 / 5 (1) Mar 06, 2014
Neutral....and ionized?


Take a glass of water and pour a little salt into it. Does it generate current if you stick wires into it? The sodium will ionize in the water, but the glass of water is neutral altogether, so you're not going to power a light bulb with it. That's too bad actually. I'd love free energy like that!!!!!!!!!

That's the heart of the problem with a lot of EU/PC propositions. They just don't understand ionization and ionized fluids.
yyz
5 / 5 (2) Mar 07, 2014
By carefully studying and modelling the gravitational lens, scientists can use this knowledge to reconstruct the appearance of the (unlensed) source. A 2006 study provided this reconstructed image of the lensed quasar/Seyfert I galaxy in RX J1131-1231:

http://inspirehep...urce.png

Details of how this image reconstruction was achieved can be found here:

http://www.aanda....-05.html

[In particular Fig 6 in the paper details the correspondence of features in the lensed system with the reconstructed image]
no fate
1 / 5 (1) Mar 07, 2014
Neutral....and ionized?


Take a glass of water and pour a little salt into it. Does it generate current if you stick wires into it? The sodium will ionize in the water, but the glass of water is neutral altogether, so you're not going to power a light bulb with it. That's too bad actually. I'd love free energy like that!!!!!!!!!

That's the heart of the problem with a lot of EU/PC propositions. They just don't understand ionization and ionized fluids.


"What is so complicated about that? Ionize a cloud of hydrogen atoms. You now have a load of free protons and a free electrons - but the charge integral over the entire cloud is still zero."

*Facepalm* - (Especially at the "neutral cloud")

Ions travelling at 1/2 C can only be accelerated by a magnetic field, or interacting magnetic fields. This is how we accelerate Ions. Claiming it is a different force is not supported by any experimental evidence.

Or a glass of salty water.

katesisco
not rated yet Mar 08, 2014
So when the spin and the magnetism are sufficient, does the bh (Light Terminus starbody) then warp time?
About this accretion of energy through galactic mergers-- how then does science explain that bh are found in the same place through time back to 14 by?
cantdrive85
1 / 5 (1) Mar 08, 2014
What is so complicated about that? Ionize a cloud of hydrogen atoms. You now have a load of free protons and a free electrons - but the charge integral over the entire cloud is still zero.

Add an electric and magnetic field and yes, it becomes slightly more complicated than that.

Take a glass of water and pour a little salt into it. Does it generate current if you stick wires into it? The sodium will ionize in the water, but the glass of water is neutral altogether

Ahhh yes, ignorance is bliss, isn't it? There may not be enough energy to power a light bulb, but it is still a battery.
http://faculty.wa...science/

Where does the misunderstanding really lie? As usual...
lomed
not rated yet Mar 11, 2014
We know that distorted spacetime affects EM fields and waves. So how does the electric/magnetic field extend out of the EH when no other EM can?
It is the difference between a static (everywhere in this post in the sense of unchanging) field and changes in the field. Changes in the field, such as EM radiation, are required to travel at c, in vacuum. Static fields don't travel (in the rest frame of the source of the field), so there is nothing preventing a black hole from having a static electric or magnetic field.
Shelgeyr
1 / 5 (1) Mar 12, 2014
Neutral....and ionized?


Take a glass of water and pour a little salt into it. Does it generate current if you stick wires into it? The sodium will ionize in the water, but the glass of water is neutral altogether, so you're not going to power a light bulb with it. That's too bad actually. I'd love free energy like that!!!!!!!!!

That's the heart of the problem with a lot of EU/PC propositions. They just don't understand ionization and ionized fluids.


Your illustration does not support your conclusion at all. Many (hopefully most, but I don't have the stats) EU/PC proponents understand ionization and ionized fluids quite well, and would gather from your chosen illustration that it is you who do not comprehend their arguments.

In other words, your saltwater illustration is worse than a straw-man argument - it is a non-sequitur.
no fate
1 / 5 (1) Mar 12, 2014
We know that distorted spacetime affects EM fields and waves. So how does the electric/magnetic field extend out of the EH when no other EM can?
It is the difference between a static (everywhere in this post in the sense of unchanging) field and changes in the field. Changes in the field, such as EM radiation, are required to travel at c, in vacuum. Static fields don't travel (in the rest frame of the source of the field), so there is nothing preventing a black hole from having a static electric or magnetic field.


An object that only exists in theory can have any property you wish to bestow upon it, but I would love to hear the theorized mechanism behind the magnetic field of a BH. Of note, it can't be the matter around the hole because "Ions travelling at 1/2 C can only be accelerated by a magnetic field", therefore they are not generating the field that is accelerating them.
russell_russell
not rated yet Apr 05, 2014
The cosmological constant. Perhaps the most startling instance of fine-tuning is the cosmological constant paradox. This derives from the fact that when one calculates, based on known principles of quantum mechanics, the "vacuum energy density" of the universe, focusing on the electromagnetic force, one obtains the incredible result that empty space "weighs" 1,093g per cubic centimetre (cc). The actual average mass density of the universe, 10-28g per cc, differs by 120 orders of magnitude from theory.

http://phys.org/n...l#ajTabs

Maybe 1,093g is what space becomes close to a BH.

The "matter" around the hole you seek. (@ no fate)

I don't know how to accelerate space without a BH to test this.
Nor can I take you to a shell where the universe undergoes expanding acceleration.
This is all I can say to you as an illiterate never versed in BH mechanics.