11.5 TEUV

The Tübingen EUV Absorption (TEUV ) tool was created to apply interstellar absorption to theoretical stellar spectra in the wavelength range < 911 Å, where bound-free absorption by interstellar elements has a string influence on observed fluxes. This has to be considered when these observations are modeled. The hot and cool components of the interstellar medium are represented in the TEUV tool.

The program is intuitive to handle and controlled via a web interface ( http://astro.uni-tuebingen.de/~TEUV) where all parameters of the interstellar components can be entered and the input model-flux table can be uploaded. For further assistance, the mouse can be hovered over the blue labels.

The following fields have to be selected or filled in:

• Contact data: The user has to enter name and email address. In case any error occurs, the administrator can contact the user for assistance.
• Upload model and observation: For a fast and easy adjustment of the parameters, the resulting model will be displayed. An observation that covers the wavelength range < 911 Å is necessary for comparison. Input model and observation must contain wavelength in Å and in increasing order in the first and flux in erg/cm²/sec/A in the second column.
• Normalization: For the first overview of the observation, model, and corrected model, a normalization of the theoretical models is necessary to match the observation. Therefore, the observed flux at 928 Å or at a chosen wavelength (< 928 Å) has to be entered.
• Instrumental resolution: TEUV can also apply a correction with a Gaussian profile to the theoretical models to account for instrumental resolution. The FWHM of tha Gaussian has to be given in Å.
• The two components: For both components, temperature in K, radial and turbulent velocities in km/sec as well as the column densities in cm^-2 of the single ions have to be entered.

After “Upload and Submit”, the theoretical model is corrected according to the given parameters. Additionally, models with a ten times larger and smaller H I and He I column densities are created. To be able to display these models, the maximum number of output wavelength points is reduced. It may take some seconds until these corrections are applied. Then, the uploaded model, observation, and corrected model are displayed. For an easier adjustment of the parameters, the user can choose to display the models with varied H I and/or He I column densities.

If the user wants to download the resulting model, the “Download your ISM_choice” button can be used. This triggers the calculation of the corrected model without normalization, for all entered wavelength points with the instrumental resolution applied. If the TEUV tool is used to determine results that are published later, the quote to cite in the acknowledgement is given at the website. The user can store the resulting file via the “Get your results file” button.