Figure 6. HR 1099 HEG lines for a 200 ks exposure. The critical benchmarking test is the ratio of the n=4 --> 2/n=3 --> 2 lines of Fe. Note that for Fe XVIII to XX the signal-to-noise is inadequate for this test. As an example, for Fe XXIII the lines above 10 Å are n=3 --> 2 lines, while below 10 Å the n=4 --> 2 lines are found. The flux missing in the plasma models from Fe XXIII is between the ionization limit (6.36 Å) and 7.2 Å.
The ASC has the expertise to analyze these data. Jeremy Drake has been the principal investigator for EUVE and ASCA studies of several late-type stars including Procyon, while Nancy Brickhouse has led several investigations of Capella, including a simultaneous observation with EUVE and ASCA, and has analyzed solar spectra. We have both established collaborations with atomic physics and solar astrophysics communities, and thus are well positioned to communicate problems as well as to facilitate the solutions of problems as they arise.
We will provide line lists which include line identifications, observed intensities, and comparisons with atomic physics calculations on a website, which will be updated on a regular basis as we develop an increasingly thorough analysis. Atomic physics calculations which will be benchmarked include branching ratios (intensity ratios from lines formed at the same upper level), collision strengths (lines from the same ions formed at different upper levels), and ionization balance (lines from different ionization states of the same element).
We will also produce documentation that describes the analysis. A publication quality article will include a literature review and comparison of atomic data from different sources.
Furthermore, we will initiate collaborations to produce new or improved atomic data with theoretical physicists. We will also initiate collaborations to develop laboratory experiments that can test critical issues not resolved by these benchmark studies.
We intend these tests to serve as an initial set of tests for collisionally ionized plasmas. As science products emerge from AXAF, new demands will be placed on the atomic models and we will respond to these demands with proposals for additional benchmarking studies using other astrophysical sources, as needed.