Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New virtual telescope zooms in on Milky Way's super-massive black hole

05.09.2008
Radio dishes in 3 states create virtual telescope 2,800 miles across

An international team, led by astronomers at the MIT Haystack Observatory, has obtained the closest views ever of what is believed to be a super-massive black hole at the center of the Milky Way galaxy.

The astronomers linked together radio dishes in Hawaii, Arizona and California to create a virtual telescope more than 2,800 miles across that is capable of seeing details more than 1,000 times finer than the Hubble Space Telescope. The cosmic target of the observations was the source known as Sagittarius A* ("A-star"), long thought to mark the position of a black hole whose mass is 4 million times that of the sun.

Though Sagittarius A* was discovered three decades ago, the new observations for the first time have an angular resolution, or ability to observe small details, that is matched to the size of the black hole "event horizon" — the region inside of which nothing, including light, can ever escape.

The concept of black holes, objects so dense that their gravitational pull prevents anything including light itself from ever escaping their grasp, has long been hypothesized, but their existence has not yet been proved conclusively. Astronomers study black holes by detecting the light emitted by matter that heats up as it is pulled closer to the event horizon. By measuring the size of this glowing region at the Milky Way center, the new observations have revealed the highest density yet for the concentration of matter at the center of our galaxy, which "is important new evidence supporting the existence of black holes," said Sheperd Doeleman of MIT, lead author of the study that will be published in the Sept. 4 issue of the journal Nature.

"This technique gives us an unmatched view of the region near the Milky Way's central black hole," Doeleman said. "The new observations have a resolution equivalent to being able to see, from Earth, a baseball on the surface of the moon."

The key to making these observations is a technique called very long baseline interferometry, or VLBI, which links simultaneous observations from several radio telescopes that can be thousands of miles apart. The signals from these radio dishes are combined to create a "virtual" telescope with the same resolving power as a single telescope as large as the distance between the participating dishes. As a result, VLBI can reveal exquisitely sharp details. To create the continent-sized telescope, the team developed and installed special equipment at four observatories: the Arizona Radio Observatory's Submillimeter Telescope (ARO-SMT) of the University of Arizona, the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in California, and both the James Clerk Maxwell Telescope (JCMT) and the Submillimeter Array (SMA) in Hawaii.

The new observations were done using very short radio waves of 1.3 millimeters wavelength, which can penetrate the fog of interstellar gas that blurs observations at longer wavelengths. Like a distant light seen through a dense mist, longer-wavelength views of the Galactic Center are dimmed and distorted. "The short wavelength observations combined with the large distances between the radio observatories is what makes this virtual telescope uniquely suited to study the black hole," said Lucy Ziurys, Director of the Arizona Radio Observatory and a co-author of the study.

Though it takes light more than 25,000 years to reach us from the center of the Milky Way, the team measured the size of Sagittarius A* to be only one-third the Earth-sun distance — a trip that light would make in only three minutes. The astronomers concluded that the source of the radiation likely originates in either a disk of matter swirling in toward the black hole, or a high-speed jet of matter being ejected by the black hole. "Future observations that create even larger virtual telescopes will be able to pinpoint exactly what makes Sagittarius A* light up," Doeleman said. "Most galaxies are now thought to have black holes at their centers, but because Sagittarius A* is in our own galaxy, it is our best chance to observe what's happening at an event horizon."

"This pioneering paper demonstrates that such observations are feasible," commented theorist Avi Loeb of Harvard University, who was not a member of the discovery team. "It opens up a new window for probing the structure of space and time near a black hole and testing Einstein's theory of gravity."

Teresa Herbert | EurekAlert!
Further information:
http://www.mit.edu

More articles from Physics and Astronomy:

nachricht Subnano lead particles show peculiar decay behavior
25.04.2018 | Ernst-Moritz-Arndt-Universität Greifswald

nachricht Getting electrons to move in a semiconductor
25.04.2018 | American Institute of Physics

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: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Getting electrons to move in a semiconductor

25.04.2018 | Physics and Astronomy

Reconstructing what makes us tick

25.04.2018 | Physics and Astronomy

Cheap 3-D printer can produce self-folding materials

25.04.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>