Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rapid galaxy merging dominates universe’s early history

20.02.2006


A new study by a researcher at The University of Nottingham has provided the first observational evidence of how massive galaxies in our universe formed.



The results of this study have major implications for many other areas of research and are being used by astronomers to explain seemingly unrelated processes such as how massive black holes and the universe’s stars came to be.

The research, led by Dr. Christopher J. Conselice of the University’s School of Physics and Astronomy, is published in the February 20th edition of the Astrophysical Journal.


It uses the deepest images taken by the Hubble Space Telescope to study galaxies when they were only two billion years old. His team has found that the majority of the most massive galaxies in the early universe are undergoing multiple and spectacular mergers.

These mergers lead to the creation of new stars from colliding gas clouds and likely feed and grow the masses of black holes lurking in the centre of all galaxies.

The work is helping to definitively confirm what scientists have long hoped for - massive galaxies form when smaller galaxies merge together - a major and previously unconfirmed prediction of the cosmological standard model.

"The results show us that the most massive galaxies we see in today’s universe, which are passive and old, were once undergoing rapid mergers with each other, which it turns out is how they form," said Conselice.

While distant galaxies have been studied for over a decade, it has until now remained a mystery how they evolved into the galaxies we see today. Young galaxies have very low masses and astronomers have long been puzzled by how these systems turn into massive galaxies in the local universe.

The Conselice results demonstrate that a typical massive galaxy in today’s universe has undergone four to five mergers with other galaxies to transform from these young low mass systems into the giant galaxies.

These mergers are very rare today, with only about one per cent of galaxies merging, whereas 10 billion years ago, nearly all massive galaxies were undergoing mergers. An analysis technique developed by Conselice over a period of more than 10 years was used on the deepest images ever taken of the universe to make these discoveries.

The results further show that massive galaxies did not form rapidly, within a few million years after the Big Bang, neither did they form gradually over an extended period of time. In a surprising finding, almost all of this merger activity occurred from the birth of the universe to about six billion years ago.

Dr. Conselice added: "Perhaps the most amazing thing about these results is that massive galaxy formation is largely over when the universe is half its current age. This means that all this merging activity was somehow curtailed by an unknown process."

The research may hold clues about the formation of our own galaxy. The Milky Way contains spiral arms, which are not thought to form through the merger process. However, at the centre of our galaxy is a spherical system of stars called a bulge - a high-density region featuring many old stars and a massive black hole, which probably formed as a result of these mergers.

The research could also help astronomers to see into the Milky Way’s future - it is possible that our galaxy will itself merge with Andromeda, our nearest neighbouring large galaxy in around a billion years from now. This would see the destruction of the spiral disk that surrounds the bulge and change dramatically the shape of our galaxy, as well as significantly altering the positions of stars we see in the night sky.

Dr. Christopher J. Conselice | alfa
Further information:
http://www.nottingham.ac.uk/~ppzcc1/massivegal.html

More articles from Physics and Astronomy:

nachricht Magnetic field traces gas and dust swirling around supermassive black hole
22.02.2018 | Royal Astronomical Society

nachricht UMass Amherst physicists contribute to dark matter detector success
22.02.2018 | University of Massachusetts at Amherst

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: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Stiffness matters

22.02.2018 | Life Sciences

Magnetic field traces gas and dust swirling around supermassive black hole

22.02.2018 | Physics and Astronomy

First evidence of surprising ocean warming around Galápagos corals

22.02.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>