Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

XMM-Newton reveals the origin of elements in galaxy clusters

11.05.2006


Deep observations of two X-ray bright clusters of galaxies with ESA’s XMM-Newton satellite allowed a group of international astronomers to measure their chemical composition with an unprecedented accuracy. Knowing the chemical composition of galaxy clusters is of crucial importance to understanding the origin of chemical elements in the Universe.



Clusters, or conglomerates, of galaxies are the largest objects in the Universe. By looking at them through optical telescopes it is possible to see hundreds or even thousands of galaxies occupying a volume a few million light years across. However, such telescopes only reveal the tip of the iceberg. In fact most of the atoms in galaxy clusters are in the form of hot gas emitting X-ray radiation, with the mass of the hot gas five times larger than the mass in the cluster’s galaxies themselves.

Most of the chemical elements produced in the stars of galaxy clusters - expelled into the surrounding space by supernova explosions and by stellar winds - become part of the hot X-ray emitting gas. Astronomers divide supernovae into two basic types: ‘core collapse’ and ‘Type Ia’ supernovae. The ‘core collapse’ supernovae originate when a star at the end of its life collapses into a neutron star or a black hole. These supernovae produce lots of oxygen, neon and magnesium. The Type Ia supernovae explode when a white dwarf star consuming matter from a companion star becomes too massive and completely disintegrates. This type produces lots of iron and nickel.


Respectively in November 2002 and August 2003, and for one and a half day each time, XMM-Newton’s made deep observations of the two galaxy clusters called ‘Sersic 159-03’ and ‘2A 0335+096’. Thanks to these data the astronomers could determine the abundances of nine chemical elements in the clusters ‘plasma’ – a gas containing charged particles such as ions and electrons.

These elements include oxygen, iron, neon, magnesium, silicon, argon, calcium, nickel, and - detected for the first time ever in a galaxy cluster - chromium. "Comparing the abundances of the detected elements to the yields of supernovae calculated theoretically, we found that about 30 percent of the supernovae in these clusters were exploding white dwarfs (‘Type Ia’) and the rest were collapsing stars at the end of their lives (‘core collapse’)," said Norbert Werner, from the SRON Netherlands Institute for Space Research (Utrecht, Netherlands) and one of the lead authors of these results.

"This number is in between the value found for our own Galaxy (where Type Ia supernovae represent about 13 percent of the supernovae ‘population’) and the current frequency of supernovae events as determined by the Lick Observatory Supernova Search project (according to which about 42 percent of all observed supernovae are Type Ia)," he continued.

The astronomers also found that all supernova models predict much less calcium than what is observed in clusters and that the observed nickel abundance cannot be reproduced by these models. These discrepancies indicate that that the details of supernova enrichment is not yet clearly understood. Since clusters of galaxies are believed to be fair samples of the Universe, their X-ray spectroscopy can help to improve the supernova models.

The spatial distribution of elements across a cluster also holds information about the history of clusters themselves. The distribution of elements in 2A 0335+096 indicates an ongoing merger. The distribution of oxygen and iron across Sersic 159-03 indicates that while most of the enrichment by the core collapse supernovae happened long time ago, Type Ia supernovae still continue to enrich the hot gas by heavy elements especially in the core of the cluster.

Norbert Schartel | alfa
Further information:
http://www.esa.int/esaSC/SEM94Q8ATME_index_0.html

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

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>