2.6 TIRO
The Tübingen Iron-Group Opacity (TIRO) service creates atomic data files and cross-section data for
radiative bound-bound and bound-free transitions of iron-group elements (calcium, scandium,
titanium, vanadium, chromium, manganese, iron, cobalt, and nickel). It is based on the program
IrOnIc that was developed at Tübingen. TIRO enables the VO user to consider iron-group
elements in model-atmosphere calculations easily, in various ways, and without spending
own calculation time for the creation of the necessary input data. It is controlled via web
interface ( http://astro.uni-tuebingen.de/~TIRO) in which the following inputs have to be
given.
- The name, institute, and email address of the user have to be given to inform the user about
the status of the process and the location of the results.
- The resulting line profiles depend on the line temperature TL. TL is 3/4 Teff and corresponds
to the mean temperature in the lineforming region.
- A frequency grid can be uploaded. The corresponding file has to be written in
plain text with monotonically increasing frequency points and must be in TMAP
( http://astro.uni-tuebingen.de/~TMAP) format. Alternatively, a start and end
wavelength as well as a spacing or maximum number of points can be chosen. The frequency
grid is then created automatically by TIRO. The calculations are performed on this frequency
grid or already calculated cross-sections from the database are interpolated to this frequency
grid.
- It is possible to retrieve data for all ionization stages up to IX. The requested ionization
stages can be chosen.
- Cross-sections for the iron-group elements can be created considering all or some of them
individually or generically. When the individual option is chosen, an easy adjustment of the
abundances in the model atmosphere calculation is possible. A generic model atom consists
of selected iron-group elements. In this case, the given abundance ratios are fixed in the
resulting model atom. For both cases the line type of the underlaying atomic data can
be selected. They are taken from Kurucz’ line lists and can be chosen between lines with
measured wavelengths (POS) or measured and calculated wavelengths in addition (LIN).
After submitting the data, the given parameters are stored in a request file. TIRO checks regularly if
requests are waiting and processes them one after the other. The user is informed via email when the
handling of the data starts. The resulting files are stored in a compressed tar archive that is accessible
via a wget command. The user is informed via email about its location. The files for bound-bound
transitions contain a table with frequencies in the first column, cross-sections in the second (calculated
for electron density 0) and in the third column (calculated for electron density 1016/cm3). The
corresponding files for bound-free transitions include a table with frequencies in the first and
cross-sections in the second column.