Space

March 7, 2014

Chandra, XMM-Newton provide direct measurement of distant black hole’s spin

Astronomers have used NASA’s Chandra X-ray Observatory and the European Space Agency’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 supermassive black holes with current X-ray observatories.

Prior to the announcement of this work, the most distant black holes 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.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines October 29, 2014

News: Unmanned rocket explodes just six seconds after taking off - A NASA rocket due to be visible across the East Coast on its way to the International Space Station has blown up on the Launchpad. IG: Former chief of wounded warrior office broke law, DOD regs - The Defense Department inspector general has recommended “corrective action”...
 
 

News Briefs October 29, 2014

F-35C makes first landing at Virginia Beach Navy base The Navy says an operational F-35C joint strike fighter has landed at Naval Air Station Oceana for the first time. Naval Air Station Oceana is the Navy’s master jet base on the East Coast. The Navy says the plane came to the Virginia Beach base Oct....
 
 

Time to turn to American technology for space launch

For the first time since the Cold War, the United States has deployed armored reinforcements to Europe. To counter Russia’s aggression, several hundred troops and 20 tanks are now in the Baltic. Yet the U.S. military is still injecting millions into the Russian military industrial complex. In late August, the United Launch Alliance – the...
 

 
Air Force photograph by Joe Davila

Boeing, Air Force demonstrate Minuteman III readiness in flight test

Air Force photograph by Joe Davila Boeing supported the launch of an unarmed Minuteman III intercontinental ballistic missile at Vandenberg Air Force Base, Calif., on Sept. 23, 2014. Boeing supported the U.S. Air Force’s succ...
 
 

Pentagon going to court for refusing to release Sikorsky data

PETALUMA, Calif. – The Pentagon is refusing to release any data on any prime contractors participating in the 25-year-old Comprehensive Subcontracting Plan Test Program. The American Small Business League launched a program in 2010 to expose the fraud and abuse against small businesses the CSPTP had allowed. As a test the ASBL requested the most...
 
 
Northrop Grumman photograph

Raytheon Griffin C flight tests demonstrate in-flight retargeting capability

Northrop Grumman photograph Northrop Grumman has received a contract from the U.S. Marine Corps for low-rate initial production of the AN/TPS-80 Ground/Air Task Oriented Radar (G/ATOR). G/ATOR is the first ground-based multi-mi...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>