095339

We propose joint TOO category Chandra/HETGS (120 ks) and XMM-Newton/RGS (40 ks)observations of the galactic black hole binary GX 339-4 during an outburst. Weaim to obtain high-quality spectra in order to study the imprints ofinterstellar gas and dust towards the source. The proposed observations willenable for the first time a simultaneous study of the OK FeL MgK SiK usingthe newest laboratory measurements of astrophysical dust templates and gas phaseabsorption models. This source provides the ideal laboratory to appropriatelyidentify the absorption features from interstellar solids and determine theirchemical composition and lattice structure which is one of the major unsolvedproblems in the astrophysics of the interstellar medium. [truncated! Please see actual data for full text]