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 A better way to weigh millions of solitary stars
15.12.2017 | Vanderbilt University

nachricht A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg

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-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>