Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Cosmic Crash of Unexpected Proportions

02.09.2011
An international research team investigates the distant galaxy cluster Abell 2744

The biggest known cosmic collision in the Universe took place in a distant galaxy cluster called Abell 2744. That is the conclusion of an international team of scientists investigating the debris of this massive crash with novel research methods that were developed at Heidelberg University’s Institute of Theoretical Astrophysics.


The image shows the galaxy cluster Abell 2744. It combines observations in the visible light spectrum with X-ray images of satellite Chandra (red) and clouds of dark matter (blue). The particularities of the system are clearly visible, for example a clump of dark matter with no stars or gas (northwest sector) and a clump of galaxies and dark matter without gas (western sector). The scale indicates a distance of 250,000 parsecs, approximately nine times the diameter of the visible part of our own galaxy, the Milky Way. In astronomy, the compass points East and West are switched, as shown at the bottom right corner of the image.
Image source: NASA, ESA, ESO, CXC, J. Merten (Heidelberg/Bologna) & D. Coe (STScl)

These methods enabled the scientists to reconstruct the course of events over a period of several hundreds of millions of years and thus to understand how large-scale structures develop in the Universe based on the interaction of different kinds of matter. Researchers from Brazil, Canada, Germany, Israel, Italy, Scotland, Spain, Taiwan and the United States of America collaborated on the investigation.

The astrophysicists observed the galaxy cluster Abell 2744 from an unprecedented number of angles with high-performance telescopes, among them the Very Large Telescope of the European Southern Observatory (ESO) in Chile, the Japanese Subaru Telescope in Hawaii and the Hubble and Chandra space telescopes. With the data gleaned from these observations, the research team headed by astrophysicist Dr. Julian Merten of the Heidelberg Institute of Theoretical Astrophysics was able to investigate the three essential components of galaxy clusters: galaxies and their stars, intergalactic gas and dark matter.

Each of the approx. 1,000 galaxies of Abell 2744 contains many billions of stars. However, this “visible” matter only makes up about five percent of the entire mass of the galaxy cluster. The galaxies “float” in the diffuse gas that is distributed between them, Dr. Merten explains. This “intergalactic gas” comprises 20 percent of the overall mass and was heated up so intensely by the effects of gravitational forces in the galaxy cluster that it emits radiation mostly in the X-ray wavelength band. The remaining 75 percent of the galaxy cluster consist of the mysterious “dark matter”.

To understand the processes going on in Abell 2744, the scientists aimed to determine the distribution of these three components as precisely as possible. This is easily accomplished for galaxies and intergalactic gas, but dark matter is much harder to pin down. It neither emits nor absorbs light and can only be detected through its gravitational attraction. However, during his time as PhD student at the Heidelberg Graduate School of Fundamental Physics, Julian Merten devised special methods for measuring the distribution of dark matter with the aid of an effect known as gravitational lensing.

When light rays emitted by galaxies far beyond Abell 2744 cut through the massive galaxy cluster, the gravitational attraction of the unevenly distributed dark matter changes the trajectory of the light travelling through the cluster. “The rays of light are ‘bent’ more or less strongly so that the images of the background galaxies appear distorted in a characteristic way,” says Dr. Merten. “By analysing this distortion for a large number of background galaxies we are able to chart out a map showing the distribution of dark matter.”

The surprising outcome of the analysis of Abell 2744 is that this system consists of at least four different galaxy clusters that must have collided over a period of about 350 million years. “The collision obviously separated the hot gas from the dark matter and led to an unusual and fascinating distribution of the three kinds of matter,” adds Dr. Merten. In the northwest sector, the scientists found an area where dark matter was separated from the other components in an unusual way. The hot gas leads the dark matter by a large distance and the galaxies do not appear to match the position of the dark matter, either. In the western sector, the researchers came across an area that contains both dark matter and galaxies, but no hot gas. “It looks as if this gas was stripped away completely in the central region of the cluster during the collision, and was left behind,” says Dr. Merten. Because of the large number of unusual and often mysterious phenomena, the researchers have dubbed Abell 2744 “Pandora’s cluster”.

A publication on these research findings entitled “Creation of Cosmic Structure in the Complex Galaxy Cluster Merger Abell 2744” will be appearing in ”Monthly Notices of the Royal Astronomical Society”. Preprint: http://arxiv.org/abs/1103.2272.

The Institute of Theoretical Astrophysics is part of Heidelberg University's Centre for Astronomy (ZAH).

Contact:
Dr. Julian Merten
Zentrum für Astronomie der Universität Heidelberg (ZAH)
Institute of Theoretical Astrophysics
phone: +49 6221 54 8987
jmerten@uni-heidelberg.de
Communications and Marketing
Press Office, phone +49 6221 54 2311
presse@rektorat.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw
Further information:
http://www.uni-heidelberg.de

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>