Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A most detailed view into distant stellar nurseries

14.06.2017

Just like in human civilizations the birth rate in the Universe fluctuated over time. When the Universe had reached 2.5 Billion years of its current age of approximately 13.8 Billion years, galaxies produced the majority of all stars ever formed. An international team of astronomers including reasearcher from the Argelander-Institute for Astronomy at the University of Bonn and the Max-Planck-Institute for Astronomy Heidelberg has now vastly improved on previous estimates. The Karl G. Jansky Very Large Array Telescope in New Mexico (USA) allowed to undertake a survey of distant galaxies that produced unprecendentedly detailed and deep radio views over such a large celestial area.

The international team thereby discovered almost 11,000 galaxies over an area equivalent to about nine full moons. Thanks to these unique data the life cycle of galaxies over the past 13 Billion years could be reconstructed. „The radio light from a galaxy can show us at least two very important things,” said the lead investigator of the project, Associate-Professor Vernesa Smolčić from the University of Zagreb.


Galaxies: Depicted in green are the visually visible and near-infrared regimes. Only at radio wavelengths (red) the hidden activities of the central black holes are unveiled.

Source: Dr. Eleni Vardoulaki und Eric Faustino Jimenez-Andrade (Argelander-Institut)/VLA-COSMOS Team

„Radio light helps us to see straight through dust clouds and so reveals new stars forming within galaxies. It can also show us highly energetic signatures of growing supermassive black holes.“

As opposed to opical light that our eyes can see, radio light is not blocked by the large clouds of interstellar dust that often reside in galaxies. This means that radio waves can be used to detect newborn stars within galaxies in a way that is not possible at other wavelengths of light.

The VLA-COSMOS project started with Dr. Eva Schinnerer at the Max-Planck Institute for Astronomy Heidelberg as principal investigator already back in 2004 with a first radio survey of a celestial area called „COSMOS“. The tremendous scientific success of this project motivated the team – now led by Prof. Smolčić who at that time was based as a researcher at the Argelander-Institute for Astronomy at the University of Bonn – to apply for a large follow-up survey. This effort only became possible thanks to a major technological upgrade the Karl G. Jansky Very Large Array (VLA) Telescope in New Mexico (USA) had undergone in the meanwhile.

Combining data from different telescopes

The astronomers combined the new radio data with optical, infrared, and X-ray information from many of the world’s leading telescopes. „The synergy of sensitive, multi-wavelength data allowed us to investigate the properties of galaxies shining at radio wavelengths out to about 13 billion years into the universe’s past,” said Dr. Alexander Karim who is responsible for the VLA-COSMOS survey at the Argelander-Institute for Astronomy at the University of Bonn.

The team found that the rate of production of new stars within galaxies was the highest when the universe was about 2.5 billion years old – a fifth of its current age. During that period, about a quarter of all newborn stars were being created in massive galaxies. They also found that up to 20 percent more star formation was occurring in galaxies in the early universe, compared to what was previously thought.

Moreover, a very distant but vigurously star forming population of galaxies – so called submillimeter-galaxies – were found to be substantially larger than previously expected. The exact reasons for this have not been entirely clarified yet but they could be linked to collisions and gravitational interactions between galaxies.

Supermassive Black Holes heat up galaxies

The new radio survey has also provided a unique insight into galaxies containing actively growing supermassive black holes in their centers. These galaxies are called Active Galactic Nuclei, or AGN for short. Matter orbiting around and falling into the black hole can release huge amounts of energy. Using the new radio data, the astronomers discovered more than 1000 AGN. Only their radio emission signatures betray their hidden black hole activity. They are particularly interesting because of their influence on the fate of their host galaxies but even on their cosmic environment. The astronomers compared the AGN heating process assumed in cosmological simulations to what they detected in the new radio data. They found a strong similarity between the two. „Physical processes associated with emission from these supermassive black holes may heat the gas in and around the galaxy, preventing the formation of new stars and halting the runaway growth of galaxies”, says Dr. Schinnerer from the MPI for Astronomy in Heidelberg. Dr. Karim adds: „The VLA-COSMOS survey marks an important milestone on our way towards the next generation large area sky surveys.”

Publication: The VLA-COSMOS 3 GHz Large Project, „Astronomy & Astrophysics“

Media contacts:

Dr. Alexander Karim
Argelander-Institut für Astronomie
Universität Bonn
+49 (0)228 73 3668
E-mail: karim@astro-uni-bonn.de

Prof. Dr. Frank Bertoldi
Argelander-Institut für Astronomie
Universität Bonn
+49 (0)228 73 6789
E-mail: bertoldi@astro-uni-bonn.de

Dr. Eleni Vardoulaki
Argelander-Institut für Astronomie
Universität Bonn
+49 (0)228 73 5659
E-mail: eleniv@astro.uni-bonn.de

Dr. Eva Schinnerer
Max-Planck-Institut für Astronomie Heidelberg
+49 (0)6221 528 293
E-mail: schinner@mpia.de

Weitere Informationen:

http://www.aanda.org/component/toc/?task=topic&id=752 Publication

https://www.youtube.com/watch?v=G9Cs6UDHKak Video: The VLA-COSMOS 3 GHz Large Project

Johannes Seiler | idw - Informationsdienst Wissenschaft

More articles from Physics and Astronomy:

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

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: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Pollen taxi for bacteria

18.07.2018 | Life Sciences

Biological signalling processes in intelligent materials

18.07.2018 | Life Sciences

Study suggests buried Internet infrastructure at risk as sea levels rise

18.07.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>