Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gemini/HST survey reveals building-block process in evolution of massive galaxy clusters

05.04.2006


A study of the Universe’s most massive galaxy clusters has shown that mergers play a vital role in their evolution.

Astronomers at Oxford University and the Gemini Observatory used a combination of data from the twin Gemini Telescopes, located in Hawaii and Chile, and the Hubble Space Telescope (HST) to study populations of stars in the Universe’s most massive galaxy clusters over a range of epochs – the earliest being half the age of the Universe. The HST images were used to map the light distribution of the galaxies in the cluster. Data from the Gemini Multi-Object Spectrograph allowed the team to analyse the light from galaxies to determine their masses, ages and chemical compositions.

“We still don’t have a clear picture of how galaxies develop over the history of the Universe. The strength of this study is that we are able to look at galaxy clusters over a range of epochs,” said Dr Jordi Barr of Oxford University, who is presenting some of the first results of the Gemini/HST Galaxy Cluster Project at the RAS National Astronomy Meeting on 5th April.



Galaxy clusters contain the most massive galaxies in the Universe. Until recently, astronomers believed that all galaxies in the centres of clusters formed rapidly and then aged without any further changes to their structure in a process known as “Passive Evolution”. Results from the Gemini/HST Galaxy Cluster Project now show that this cannot be the case.

Dr Barr explained, “When we’re looking at the most distant galaxy clusters, we are looking back in time to clusters that are in early stages of their formation. The young galaxies in distant clusters appear to be very different from those in the mature clusters that we see in the local Universe. We found the earliest galaxy clusters have a huge variation in the abundances of elements such as oxygen and magnesium, whereas the chemistry of galaxies in the sample of closer clusters appears to be much more homogenous. This difference in chemistry proves that the clusters must actively change over time. If the galaxies in the old clusters have acquired a complete ‘set’ of elements, it’s most likely that they have formed from the mergers of several young galaxies”.

The group found that the star-formation in galaxies is dependent on mass and that in lower mass galaxies star-formation continues for longer. The most massive galaxies in clusters appear to have formed all their stars by the time the universe is just over a billion years old, whereas the lower mass galaxies finish forming their stars some 4 billion years later.

“We see the effects of star-formation in low mass galaxies but are unsure about why it’s happening. It’s possible that star-formation can be shut down very rapidly in dense environments and that the lower mass galaxies are recent arrivals that are forming stars over a longer period outside the cluster, then falling in. But we are still speculating...” said Dr Barr

The group’s observations of merging galaxy clusters showed that a large proportion of the galaxies in those clusters have undergone recent bursts of star formation. This indicates that star formation may be triggered if galaxies are thrown, during the course of a merger, into contact with the gaseous medium pervading the cluster.

Future observations are planned at X-ray wavelengths to study the interactions between galaxies and the distribution and temperature of the surrounding gas.

Anita Heward | alfa
Further information:
http://hubblesite.org/gallery/album/entire_collection/pr2003001a/
http://www-astro.physics.ox.ac.uk/~jmb/

More articles from Physics and Astronomy:

nachricht Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa

nachricht Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik

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: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

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...

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

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>