Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cornell study finds that galaxies cluster near dark matter

24.04.2006


Courtesy Volker Springel and the Millennium Simulation group - A computer simulation of the distribution of "dark" matter at an early point in the history of the universe. The observations by Cornell’s Duncan Farrah and colleagues provide solid evidence that galaxies in the distant past trace this matter distribution very well and that these galaxies will eventually reside in extremely rich clusters of galaxies at the current epoch.


Try mixing caramel into vanilla ice cream -- you will always end up with globs and swirls of caramel. Scientists are finding that galaxies may distribute themselves in similar ways throughout the universe and in places where there is lots of so-called dark matter.

"Our findings suggest that unseen dark matter -- which emits no light but has mass -- has had a major effect on the formation and evolution of galaxies, and that bright active galaxies are only born within dark matter clumps of a certain size in the young universe," said Cornell University research associate Duncan Farrah, the lead author of a paper on spatial clustering that appeared in the April 10 issue of Astrophysical Journal Letters.

To investigate the spatial distribution of galaxies, Farrah used data that recently became available from the Spitzer Wide-area InfraRed Extragalactic (SWIRE) survey, one of the largest such surveys performed by the Spitzer Space Telescope, which was launched in 2003.



A galaxy is typically made up of hundreds of billions of stars grouped tightly together. But galaxies themselves often group together into what astronomers call "large-scale structures." And, just as galaxies themselves can take on such shapes as ellipticals and spirals, so, too, can the large-scale structures, ranging from galaxy clusters to long filaments of galaxies to large, empty voids.

"You might think that galaxies are just distributed randomly across the sky, like throwing a handful of sand onto the floor," said Farrar. "But the problem is they are not, and this has been a great puzzle."

Farrah is interested in how large-scale structures form. To measure the amount of clustering in the early universe, he looked at light that had traveled for several billion years from extremely distant galaxies. From this he was able to calculate the amount of bunching in candidate galaxy clusters in the early universe.

"We wanted to find the beacons of the first stages of the formation of a galaxy cluster because, at that time, the clusters themselves had not formed yet," said Farrah.

In particular, he was interested in objects that emit strongly in the infrared and are surrounded by dense gas and dust. These objects, known as ultraluminous infrared galaxies (ULIRGs), were thought to be precursors of galaxy clusters. Farrah confirmed this by showing that ULIRGs do, indeed, tend to cluster in their early phases. The ability to pinpoint the locations of nascent galaxy clusters will enable researchers to investigate early cluster formations and when they occurred.

Farrah’s finding that distant ULIRGs are linked with large clumps of dark matter was surprising for another reason. As its name suggests, dark matter doesn’t emit light so no conventional telescope can see it. However, because dark matter has mass, its existence can be inferred by the way stars are drawn to regions where this mysterious mass is concentrated.

Unexpectedly, Farrah found that ULIRGs at different points in the history of the universe coincide with clumps of dark matter haloes of very similar masses. This observation suggests that a minimum amount of dark matter is necessary for galaxies to form and to coalesce into clusters. Farrah believes his study also provides valuable insights into understanding how dark matter helped mold the evolution of the universe.

Carol Lonsdale of NASA’s Jet Propulsion Laboratory, which manages the Spitzer Space Telescope, is the principal investigator for the SWIRE project.

Graduate student Alex Kwan is a Cornell News Service writer intern.

Press Relations Office | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Physics and Astronomy:

nachricht Scientists reach back in time to discover some of the most power-packed galaxies
28.02.2017 | Clemson University

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

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: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Existence of a new quasiparticle demonstrated

28.02.2017 | Materials Sciences

Sustainable ceramics without a kiln

28.02.2017 | Materials Sciences

Biofuel produced by microalgae

28.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>