Flow diagram of TheoSSA. The VO user sends an SED request to the GAVO database by entering the photospheric parameters. If a suitable model is available within the desired tolerance limits, it is offered as a results table. In case that the parameters are not exactly matched, the VO user may decide to calculate a model with the exact parameters. TMAW will start a model-atmosphere calculation at our institute’s (IAAT) PC cluster then. Extended model grids make use of computer resources that are provided by AstroGrid-D. As soon as the model is converged, the VO user can retrieve the SED table from the GAVO database.

Temperature and density structure and ionizations fractions of our model with and log g = 7.60. IG denotes a generic model atom consisting of Ca, Sc, Ti, V, Cr, Mn, and Co.

Synthetic line profiles of C iii– iv, N iii– v, Si iii– iv, P iv– v, S iv– v, and Ge iv– v calculated from models with 57   000   K ≤ T_eff ≤ 62   000   K and log g = 7.6 compared with FUSE and STIS observations. The small horizontal bars, labeled with the element’s name, indicate T_eff where the ionization balance is best reproduced. The lines are identified at the top. “is” denotes interstellar origin. In the cases of C iv λλ   1548,1550 Å, C iv λλ   1548,1550 Å, and Si iii λλ   1206.500,1206.555 Å, the photospheric line profile is shown by a dashed, blue line (for the model at the top only).

Same as Fig. 10 for Fe iv– vi lines (from left to right panels, marked blue in the top panels) only.

Same as Fig. 10 for Ni iv– vi lines (from left to right panels, marked green in the top panels) only.

Comparison of our model spectra (all calculated with log g = 7.60) with the STIS observation. Top: final homogeneous model (TMAP). The stratified NGRT models have T_eff = 65 000 K, 60 000 K, 55 000 K, and 50 000 K (from top to bottom). The lines in the models are marked.

Comparison of the FUSE observation with our final model. Stellar and interstellar lines are identified. “is” denotes interstellar origin, “unid.” denotes unidentified lines.

Comparison of a section of the STIS observation with our final model. Stellar and interstellar lines are identified. “is” denotes interstellar origin, “unid.” denotes unidentified lines.