X-ray spectroscopy of interstellar dust: from the laboratory to the Galaxy

In this thesis, we present new laboratory data of interstellar dust analogues. These measurements, were transformed to interstellar dust models and were used to fit the spectra of low-mass X-ray binaries located in the Galactic center neighborhood in order to determine the dust properties along those lines of sight. In these spectra, we focus in particular on the Si K-edge. The XAFS features in the Si K-edge offer a range of possibilities to study silicon-bearing dust, such as investigating the crystallinity, abundance and the chemical composition. We also present a study on the prospects of observing carbon, sulfur, and other lower abundance elements (namely Al, Ca, Ti and Ni) present in the interstellar medium using future X-ray instruments. We simulated data of instruments with characteristics of resolution and sensitivity of the Athena, XARM and Arcus concepts. Lastly, we explore the theory of X-ray scattering for a new parameter space where the small angle approach is no longer valid and where the size distribution of the dust includes large (> 1 micron) particles. We apply this theory to the environment of stellar debris disks where such conditions apply. We use as a best test case the debris disk of AU Microscopii.