Multiwavelength study of X-ray emitting A- and B-stars testing the   companion hypothesis
  We report on the first results of a multi-wavelength approach to test the hypothesis that the X-ray emission from intermediate-mass stars is generated by late-type magnetically active companions. Our high spatial resolution observations of A/B-type stars in the IR using adaptive optics uncover hypothetical companion stars at arcsecond separations from the primary. The same targets are then followed-up in X-rays with Chandra to pinpoint the X-ray source. Finally, those A/B-type stars that are still detected with Chandra are studied with IR spectroscopy, where we search for temperature sensitive features indicating the existence of even closer cool companions. 
B. Stelzer, N. Huelamo, S. Hubrig, G. Micela, H. Zinnecker, E.   Guenther