Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



More Research Links Dark Matter To Galaxy Formation

Computer simulation of the distribution of dark matter at an early point in the history of the universe. Image credit: Volker Springel/Millennium Simulation
by Alex Kwan
Ithaca NY (SPX) Apr 20, 2006
Try mixing caramel into vanilla ice cream and 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," Farrah said.

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.

Related Links
SWIRE
Spitzer



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


Infrared Space Observatory Provides First View Of Monster Stars Being Born
Heidelberg, Germany (SPX) Apr 20, 2006
ESA scientists using data from the now-inoperative Infrared Space Observatory have captured the first look at the birth of monstrous stars that shine 100,000 times more brightly than the Sun. The discovery could reveal why only some regions of space seem to promote the growth of these massive stars.







  • SPACEHAB Seeking New Government Business
  • Lula Decorates First Astronaut Of Brazil
  • Malaysia Conference Considers How To Practice Islam In Space
  • Aeroflex Expands Their Radhard MSI Logic Multipurpose Transceiver Family

  • Opportunity Heads Toward Victoria
  • New Mineral History Shows That Young Mars May Have Supported Life
  • New NASA Mars Orbiter Gears Up More Instruments
  • Aeroflex Actuators Providing Smooth Motion On MRO Satellite

  • Atlas 5 Launches ASTRA 1KR Satellite
  • Cadet-Designed Rocket Blasts Off From California
  • Ariane 5 Receives Instrument Package
  • JCSAT-9 Launches From Boeing's Platform At Sea

  • SAIC Acquires Geo-Spatial Technologies
  • GeoEye To Keep An Eye On Farming Crop Subsidies For Europe
  • Unmanned Aerial Vehicles Gauge Indian Ocean Pollutants
  • Unmanned Aerial Vehicles Gauge Indian Ocean Pollutants

  • Xena Poses A Bright Mystery
  • Tenth Planet Only Slightly Bigger Than Pluto
  • New Horizons Payload Gets High Marks on Early Tests
  • "Zero G and I Feel Fine"

  • More Research Links Dark Matter To Galaxy Formation
  • Infrared Space Observatory Provides First View Of Monster Stars Being Born
  • Killer GRB Unlikely In The Galactic Neighborhood
  • Exploding Star Within A Star Surprises Astronomers

  • Lunar Rocks Suggest Meteorite Shower
  • NASA Seeking Lunar Exploration Ideas
  • Reiner Gamma Swirl: Magnetic Effect Of A Cometary Impact
  • New NASA Ames Spacecraft To Look For Ice At Lunar South Pole

  • Spirent To Supply Testing Equipment For Galileo
  • New Student-Designed System Tracks Firefighter And Special Forces
  • Russia And India Discuss Military Element For GLONASS
  • Germany's Gateway To The World

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement