Featured Research

from universities, journals, and other organizations

Substructure Maps Show That Dark Matter Clumps In Galaxies

Date:
January 19, 2005
Source:
Yale University
Summary:
Hubble Space Telescope data, analyzed by a Yale astronomer using gravitational lensing techniques, has generated a spatial map demonstrating the clumped substructure of dark matter inside clusters of galaxies.

Gravitational lensing image of galaxies (yellow to red) and haloes from clumped dark matter (blue).
Credit: Image courtesy of Yale University

New Haven, Conn. -- Hubble Space Telescope data, analyzed by a Yale astronomer using gravitational lensing techniques, has generated a spatial map demonstrating the clumped substructure of dark matter inside clusters of galaxies.

Clusters of galaxies (about a million, million times the mass of our sun), are typically made up of hundreds of galaxies bound together by gravity. About 90 percent of their mass is dark matter. The rest is ordinary atoms in the form of hot gas and stars.

Although little is known about it, cold dark matter is thought to have structure at all magnitudes. Theoretical models of the clumping properties were derived from detailed, high resolution simulations of the growth of structure in the Universe. Although previous evidence supported the "concordance model" of a Universe mostly composed of cold, dark matter, the predicted substructure had never been detected.

In this study, Yale assistant professor of astronomy and physics Priyamvada Natarajan and her colleagues demonstrate that, at least in the mass range of typical galaxies in clusters, there is an excellent agreement between the observations and theoretical predictions of the concordance model.

Using gravitational lensing made it possible for the observers to visualize light from distant galaxies as it bent around mass in its way. This allowed the researchers to measure light deflections that indicated structural clumps in the dark matter.

"We used an innovative technique to pick up the effect of precisely the clumps which might otherwise be obscured by the presence of more massive structures," said Natarajan. "When we compared our results with theoretical expectations of the concordance model, we found extremely good agreement, suggesting that the model passes the substructure test for the mass range we are sensitive to with this technique."

"We think the properties of these clumps hold a key to the nature of dark matter -- which is presently unknown," said Natarajan. "The question remains whether these predictions and observations agree for smaller mass clumps that are as yet undetected."

Co-author on the study, funded by Yale University, is Volker Springel, MPA, Garching, Germany. Other collaborators include.Jean-Paul Kneib, LAM - OAMP, Marseille, France, Ian Smail, University of Durham, U.K., and Richard Ellis of Caltech.

###

Citation: Astrophysical Journal Letters 617: L13-L16 (December 10, 2004)

Priyamvada Natarajan: http://www.astro.yale.edu/priya/

Astronomy: http://www.astro.yale.edu/

Physics: http://www.physics.yale.edu/


Story Source:

The above story is based on materials provided by Yale University. Note: Materials may be edited for content and length.


Cite This Page:

Yale University. "Substructure Maps Show That Dark Matter Clumps In Galaxies." ScienceDaily. ScienceDaily, 19 January 2005. <www.sciencedaily.com/releases/2005/01/050110122618.htm>.
Yale University. (2005, January 19). Substructure Maps Show That Dark Matter Clumps In Galaxies. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2005/01/050110122618.htm
Yale University. "Substructure Maps Show That Dark Matter Clumps In Galaxies." ScienceDaily. www.sciencedaily.com/releases/2005/01/050110122618.htm (accessed April 24, 2014).

Share This



More Space & Time News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Reuters - US Online Video (Apr. 23, 2014) A group of space explorers say the chance of a city-obliterating asteroid striking Earth is higher than scientists previously believed. Deborah Gembara reports. Video provided by Reuters
Powered by NewsLook.com
Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
Two US Astronauts Step out on Spacewalk for ISS Repairs

Two US Astronauts Step out on Spacewalk for ISS Repairs

AFP (Apr. 23, 2014) Two US astronauts stepped out on a brief spacewalk Wednesday to install a backup computer at the International Space Station after one failed earlier this month. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins