Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

VLA Gives Deep, Detailed Image of Distant Universe

02.05.2013
Staring at a small patch of sky for more than 50 hours with the ultra-sensitive Karl G. Jansky Very Large Array (VLA), astronomers have for the first time identified discrete sources that account for nearly all the radio waves coming from distant galaxies.

They found that about 63 percent of the background radio emission comes from galaxies with gorging black holes at their cores and the remaining 37 percent comes from galaxies that are rapidly forming stars.


"The sensitivity and resolution of the VLA, following its decade-long upgrade, made it possible to identify the specific objects responsible for nearly all of the radio background emission coming from beyond our own Milky Way Galaxy," said Jim Condon, of the National Radio Astronomy Observatory (NRAO). "Before we had this capability, we could not detect the numerous faint sources that produce much of the background emission," he added.

Previous studies had measured the amount of radio emission coming from the distant Universe, but had not been capable of attributing all the radio waves to specific objects. In earlier observations, emission from two or more faint objects often was blurred or blended into what appeared to be a single, stronger source of radio waves.

"Advancing technology has revealed more and more of the Universe to us over the past few decades, and our study shows individual objects that account for about 96 percent of the background radio emission coming from the distant Universe," Condon said. "The VLA now is a million times more sensitive than the radio telescopes that made landmark surveys of the sky in the 1960s," he added.

In February and March of 2012, Condon and his colleagues studied a region of sky that previously had been observed by the original, pre-upgrade, VLA, and by the Spitzer space telescope, which observes infrared light. They carefully analyzed and processed their data, then produced an image that showed the individual, radio-emitting objects within their field of view.

Their field of view, in the constellation Draco, encompassed about one-millionth of the whole sky. In that region, they identified about 2,000 discrete radio-emitting objects. That would indicate, the scientists said, that there are about 2 billion such objects in the whole sky. These are the objects that account for 96 percent of the background radio emission. However, the researchers pointed out, the remaining 4 percent of the radio emission could be coming from as many as 100 billion very faint objects.

Further analysis allowed the scientists to determine which of the objects are galaxies containing massive central black holes that are actively consuming surrounding material and which are galaxies undergoing rapid bursts of star formation. Their results indicate that, as previously proposed, the two types of galaxies evolved at the same rate in the early Universe.

"What radio astronomers have accomplished over the past few decades is analogous to advancing from the early Greek maps of the world that showed only the Mediterranean basin to the maps of today that show the whole world in exquisite detail," Condon said.

Condon worked with William Cotton, Edward Fomalont, Kenneth Kellermann, and Rick Perley of NRAO; Neal Miller of the University of Maryland; and Douglas Scott, Tessa Vernstrom, and Jasper Wall of the University of British Columbia. The researchers published their work in the Astrophysical Journal.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Dave Finley | Newswise
Further information:
http://www.nrao.edu

More articles from Physics and Astronomy:

nachricht Tune your radio: galaxies sing while forming stars
21.02.2017 | Max-Planck-Institut für Radioastronomie

nachricht Breakthrough with a chain of gold atoms
17.02.2017 | Universität Konstanz

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>