Interstellar X-ray Absorption Spectroscopy of Oxygen, Neon, and Iron   with the Chandra LETGS Spectrum of X0614+091
  We find resolved interstellar O K, Ne K, and Fe L absorption spectra in the Chandra Low Energy Transmission Grating Spectrometer spectrum of the low mass X-ray binary X0614+091. We measure the column densities in O and Ne, and find direct spectroscopic constraints on the chemical state of the interstellar O. These measurements probably probe a low-density line of sight through the Galaxy and we discuss the results in the context of our knowledge of the properties of interstellar matter in regions between the spiral arms. 
Frits Paerels, A. C. Brinkman, R. L. J. van der Meer, J. S. Kaastra,   E. Kuulkers, A. J. F. den Boggende, P. Predehl, Jerem...