Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Missing link found between old and young star clusters

08.01.2003


One and a half billion years ago the small, inconspicuous galaxy Messier 82 (M82) almost smashed into its large, massive neighbour galaxy Messier 81 (M81), causing a frenzy of star formation.



New research by astronomers from the Universities of Cambridge and Utrecht, Netherlands, has now discovered an elusive phenomenon in this violent "starburst" area. About 100 star clusters have been discovered that are believed to be the ancestors of the so-called "globular clusters" thought to be the oldest building blocks of galaxies.

"Such an intermediate-age population of massive, compact star clusters has been searched for extensively, but unsuccessfully until now," said Dr Richard de Grijs from the University of Cambridge’s Institute of Astronomy, and lead scientist on the project. "The fact that we have finally found such a population is evidence that formation of long-lived star clusters is indeed happening now, just as it has in the early Universe and ever since."


Dr de Grijs and his colleagues Henny Lamers and Nate Bastian, using images of M82 from the Hubble Space Telescope, found a population of about 100 star clusters aged 1.5 billion years. This is half-way down its evolution to old age - it is thought the star clusters could survive the next 10 billion years.

M82, which is 11 million light years away, is the closest starburst galaxy to Earth and is close enough to allow Hubble to see many individual star clusters.

During M82’s collision with its neighbouring galaxy, M81, the interstellar gas clouds were strongly compressed because of gravitational effects of the mass of M81, causing intense star formation activity.

Such strong starbursts have not occurred in our Milky Way galaxy for billions of years and none, until this discovery, have yet evolved sufficiently far.

"Clusters are disrupted much faster in M82 than here," said Dr de Grijs. "This is probably another after-effect of the near collision with M81. M82 has a more disturbed appearance than other nearby, well-behaved galaxies because of the more inhomogeneous distribution of interstellar gas in the galaxy caused by the near collision."

Stars are most often born in large clusters, originating from gas clouds that collapse due to their self-gravitation.

Astronomers have found thousands of star clusters in and around our Milky Way galaxy, and the populations of star clusters in neighbouring galaxies have been charted extensively as well.

Since all stars in a cluster - ranging from 1000 up to a million or more - are born more or less simultaneously, a cluster’s age can be determined fairly accurately; star clusters can therefore be used as astronomical "clocks", tracing the events that created them.

The most ancient clusters in our Milky Way galaxy - so-called "globular clusters" - are about 12 billion years old, older than the Milky Way in its present form. These globular clusters have always been considered the oldest building blocks of galaxies.

The majority of galaxies go through epochs in which the rate of star formation rises explosively, a so-called starburst. Such epochs can be traced back through the ages of star clusters: entire populations of star clusters of roughly similar age are found to form during such starburst events.

However, a strange anomaly persisted in the observations: both young, unevolved and old, fully evolved star cluster populations were known - and such populations continue to be detected routinely - but clusters half-way on that career track were missing.

This anomaly gave credibility to the theory that cluster formation in the early Universe was fundamentally different from that at present.

However, since cluster formation is closely associated with the formation and evolution of stars and galaxies in general, fundamental doubts about the evolution of the Universe as a whole were raised.

The research team consists of: Dr Richard de Grijs, Institute of Astronomy, University of Cambridge Professor Henny Lamers and Mr. Nate Bastian, Astronomical Institute, Utrecht University, The Netherlands. This research will be published in The Astrophysical Journal (Letters) of 20 January 2003.

Laura Morgan | alfa

More articles from Physics and Astronomy:

nachricht NASA's James Webb Space Telescope completes final cryogenic testing
21.11.2017 | NASA/Goddard Space Flight Center

nachricht Previous evidence of water on mars now identified as grainflows
21.11.2017 | US Geological Survey

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>