XMM-Newton traces dark matter in faint, distant galaxy groups

XMM-Newton traces dark matter in faint, distant galaxy groups
ESA "20 Jan 2010"
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=46322
Dark Matter in Distant Galaxy Groups Mapped for the First Time | Universe Today
"Dark matter (actually cold, dark – non-baryonic – matter) can be detected only by its gravitational influence. "
http://www.universetoday.com/2010/02/21/dark-matter-in-distant-galaxy-groups-mapped-for-the-first-time/
A WEAK LENSING STUDY OF X-RAY GROUPS IN COSMOS
http://www.iop.org/EJ/abstract/0004-637X/709/1/97