General X-ray properties of hot, massive stars

The recent X-ray observatories have not yet provided a large survey comparable (in sky coverage) to that based upon the ROSAT All-Sky Survey (RASS). However, two limited surveys exist : the 2XMM catalog for XMM-Newton (294 OB stars detected) and the Carina large-scale survey from Chandra (129 OB stars detected). Medium-resolution (CCD) spectra were analyzed and led to new results on the relationship between the X-ray luminosity and the bolometric luminosity, as well as on the typical properties (plasma temperature, variability) of these objects. This contribution thus presents the results of the first high-sensitivity investigation of the overall high-energy properties of a sizeable sample of hot stars.