Attacking the X-ray emission properties of young stars with the Sword of   Orion
  We present a survey of X-ray emission from young stars in the Sword of Orion star-formation region using XMM-Newton's EPIC detectors. We find over 850 X-ray sources, of which more than 700 have near-infrared counterparts consistent with being young stars. The survey enables statistical investigation of the dependence of X-ray emission properties of young stars on fundamental stellar parameters (mass, rotation, age) and environmental features (circumstellar disk, active accretion, circumstellar absorption), and study of structure size in individual coronae through analysis of large flares. 
K. R. Briggs (1), M. Guedel (1), M. Audard (2), K. W. Smith (3) ((1)   Paul Scherrer Institut, Villigen PSI, Switzerland; (2...