Observation of material circling a supermassive black hole

Jan 10, 2005
Observation of material circling a supermassive black hole

Astronomers from the University of Oxford and around the world have observed clumps of X-ray-emitting gas whipping around a black hole at 33,000 kilometres per second, one-tenth the speed of light.
The observation marks the first time scientists have been able to trace individual blobs of gas on a complete journey around a massive black hole, and provides crucial measurements that have long been missing from black hole studies: both an orbital period and an orbital speed. These have allowed the astronomers to calculate a lower limit to the black hole mass of 300,000 times that of our Sun.

The observation was made with the EPIC X-ray cameras on the European Space Agency's XMM-Newton satellite, and the team comprises Dr Jane Turner, of NASA's Goddard Space Flight Center and University of Maryland Baltimore County, Dr Lance Miller of Oxford University's Department of Physics, Dr James Reeves (NASA/GSFC) and Dr Ian George (NASA/GSFC and UMBC).

Dr Lance Miller said: 'If the black hole in question were placed in our Solar System, it would be as wide as Mercury's orbit, with the three clumps of matter detected orbiting as far out as Jupiter. They orbit the black hole in a lightning-quick 27 hours, compared to the 12 years it takes Jupiter to orbit the Sun.'

The EPIC instrument (European Photon Imaging Camera) used to make these observations was built by four countries, led by the University of Leicester where Professor Martin Turner is the Principal Investigator.

Professor Turner said: "When we designed the EPIC instrument for XMM-Newton, we hoped that it could be used to study the matter orbiting a black hole under its intense gravitational field. It is gratifying that scientists from the UK and the United States are able to do just that."

Black holes are regions in space so dense that gravity prevents all matter and light from escaping. What scientists see is not the black hole itself but rather the light emitted close to it as matter falls towards the black hole and heats to high temperatures. The scientists observed a well-known galaxy named Markarian 766, about 170 million light years away. The black hole there is relatively small, although still several million times as massive as our Sun, and highly active in swallowing gas and matter.

Matter funnels into this black hole like water swirling down a drain, forming what is called an accretion disk. Flares erupt on this disk through an unknown process. Dr Miller said: 'Calculating the flares' speeds and the black hole mass was straightforward, based on Doppler shifting, the phenomenon by which light appears to rise in energy as an object moves towards us and then fall in energy as it moves away. The 'eeeeeeyyoool' sound of a passing car on a motorway is a similar phenomenon, and Doppler shift is measured in the radar guns that police use to catch speeders.

'We think we're viewing the accretion disk at a slightly tilted angle, and we see the light from each of these flares rise and fall in energy as they orbit the black hole. With a measured velocity and orbital period, we could determine the black hole mass using relatively simple Newtonian physics.'

Two factors made the measurement possible. First, the scientists observed particularly persistent flares for nearly 27 hours. Second, no telescope before XMM-Newton has had the light-collecting power to allow for a comparison of energy over time.

The observation confirms an XMM-Newton result announced by a European team in September that some scientists had found speculative: that something as detailed as an orbital period could be detected with the current generation of telescopes. The results show that scientists, given long observation times, are now able to make measurements of black holes to test theories of how such extreme objects form at the centres of galaxies, and how they become active in swallowing gas and other matter.

Source: PPARC

Explore further: What was here before the solar system?

Related Stories

How researchers listen for gravitational waves

May 28, 2015

A century ago, Albert Einstein postulated the existence of gravitational waves in his General Theory of Relativity. But until now, these distortions of space-time have remained stubbornly hidden from direct ...

NASA telescopes set limits on space-time quantum 'foam'

May 28, 2015

A team of scientists has used X-ray and gamma-ray observations of some of the most distant objects in the universe to better understand the nature of space and time. Their results set limits on the quantum ...

Scientists one step closer to mimicking gamma-ray bursts

May 27, 2015

Using ever more energetic lasers, Lawrence Livermore researchers have produced a record high number of electron-positron pairs, opening exciting opportunities to study extreme astrophysical processes, such ...

Hubble video shows shock collision inside black hole jet

May 27, 2015

When you're blasting though space at more than 98 percent of the speed of light, you may need driver's insurance. Astronomers have discovered for the first time a rear-end collision between two high-speed ...

A solar eclipse sheds light on physics

May 26, 2015

On 29 May 1919, a shadow dance took place over the Caribbean which was to make history: While the new moon covered the blazingly bright disk of the Sun, astronomers around Arthur Stanley Eddington measured ...

Recommended for you

What was here before the solar system?

May 29, 2015

The solar system is old. Like, dial-up-fax-machine-old. 4.6 billion years to be specific. The solar system has nothing on the universe. It's been around for 13.8 billion years, give or take a few hundred ...

What is lunar regolith?

May 29, 2015

When you're walking around on soft ground, do you notice how your feet leave impressions? Perhaps you've tracked some of the looser earth in your yard into the house on occasion? If you were to pick up some ...

Herschel's hunt for filaments in the Milky Way

May 29, 2015

Observations with ESA's Herschel space observatory have revealed that our Galaxy is threaded with filamentary structures on every length scale. From nearby clouds hosting tangles of filaments a few light-years ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.