Laboratory-based standards for interpreting X-ray spectra from celestial sources

High sensitivity, high resolution instrumentation flown on the Chandra, XMM-Newton, and Suzaku X-ray observatories have provided X-ray astrophysicists with relatively straightforward access to powerful line diagnostics that tightly constrain the physical parameters of celestial sources. Accurate measurements of transition energies, line shapes, and intensities provide, for example, quantitative measures of velocity fields, electron densities, and temperatures. X-ray measurements probe sources unattainable by any other wavelength bands, such as the regions of accretion disks near black holes, and the hot intracluster medium in clusters of galaxies. Thus, X-ray astronomy in the age of Chandra, XMM-Newton, and Suzaku provides important information necessary to understand the formation and evolution of galaxies, stars, the phenomena near black holes, and the evolution of the universe as a whole. Beginning in 2015 with the launch of the Astro-H X-ray Observatory, high throughput, high resolution X-ray spectroscopy of extended sources in the Fe K band will be available for the first time, making it possible to unravel the mysteries of some of the most energetic objects in our Universe. Accurate, unambiguous interpretation of high quality, high resolution spectra from these premier observatories requires laboratory-tested spectral models. Starting over twenty years ago, the electron beam ion trap facility at Lawrence Livermore National Laboratory has produced a plethora of highly accurate data to satisfy this requirement, and has also addressed specific problems found to be beyond any modeling capability. As part of this work, a variety of new measurement techniques and instruments, including the NASA/GSFC ECS calorimeter, have been developed. More recently, the portable FLASH-EBIT, built and maintained at the Max Planck Institute for Nuclear Physics and coupled to third and fourth generation light sources has opened new measurement regimes, i.e., the ability to probe the atomic structure of highly charged ions using high resolution, high intensity photon beams. Selected results will be presented. Work performed under auspices of U.S. D.o.E. by DE-AC52-07NA27344 and supported by NASA grants to LLNL and GSFC.