Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dark matter haloes favour Frisbee over Rugby

20.04.2007
A new study of dark matter haloes indicates that they are shaped like Frisbees, not Rugby-balls as has been suggested. Aaron Robotham, of the University of Bristol, will be presenting the results at the Royal Astronomical Society’s National Astronomy Meeting in Preston on Friday 20th April.

A group from the University of Bristol and the Cerro-Tololo Inter-American Observatory in Chile has developed a sophisticated computer model to work out the three-dimensional shape of the dark matter using the positions of groups of galaxies which are embedded the haloes. Dark matter haloes are studded with galaxies but being discrete objects the true halo shape may not be apparent by just simply measuring their distribution.

The new model is able to fill in the gaps with an unprecedented degree of accuracy, presenting a truer picture of the shape of the ellipsoids. The results for the corrected data show that the dark matter haloes are non-spherical but flattened out like a Frisbee, most preferentially in the smallest groups of galaxies. When the group had analysed the raw data the ellipsoids had appeared to be shaped like a Rugby ball or American Football, which was also the shape preferred by previous studies.

“Our findings are that dark matter haloes are Frisbee shaped, that means that dark matter is not simply spherically distributed, and indicates that filamentary structure is not a strong influence on the shape of the group halo- prolate shapes would be strongly favoured in this case” said Robotham. “The apparent oblate shapes that are allowed after correction mirrors that seen for the Local Group and has often been suggested in computer models.”

The shape of dark matter haloes gives us information about how the early universe formed and how the haloes have evolved. According to cosmological theory, soon after the Big Bang cold dark matter formed the universe’s first large-scale structures, which then collapsed under their own weight to form vast halos. The gravitational pull of these haloes sucked in normal matter and provided a focus for the formation of galaxies. How the shape of these halos have evolved over time is a subject of much debate, complicated by a vast number of factors that mean extremely large samples are required in order to extract meaningful statistics.

The scientists used the 2-degree Field Percolation Inferred Galaxy Groups (2PIGG) catalogue, the largest survey of galaxy groups that is publicly available. The group’s findings have been submitted for publication in the Astrophysical Journal.

Anita Heward | alfa
Further information:
http://www.nam2007.uclan.ac.uk/info.php
http://www.ras.org.uk//index.php?option=com_content&task=view&id=1181

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>