Wolf-Rayet Stars in the Galatic center: modeling and analyzing infrared spectra

• Applicant: Professor Dr. Wolf-Rainer Hamann
• Subject Area: Astrophysics and Astronomy
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 21215198

Presently the infrared spectral range enjoys an unprecedented importance, promoted by recent and upcoming observing instruments. Ground-based telescopes, especially in connection with adaptive optics and integral-field spectroscopy, combine highest spatial resolution with high efficiency in the near infrared, while space-based instruments give access to wider wavelength ranges. Of paramount interest is the Galactic center, which is obscured by dust clouds and therefore only observable at infrared wavelengths. Many hot, massive stars populate this enigmatic region. However, a purely infrared-based spectral analysis of stars with strong stellar winds (especially so-called Wolf-Rayet stars) is still in its infancy. Our group developed theoretical models for this kind of stellar atmospheres and their emergent spectra. The project proposed here will open the access to the IR range in modeling and analyzing Wolf-Rayet star spectra. We will carefully synthesize the IR spectra in our numerical calculations. As the number of observable spectral lines in the IR is limited, parameter studies must reveal the significance and uniqueness of IR-restricted analyses. The methods shall be verified first by means of stars which are also accessible in the visible range. Subsequently we will analyze stars close to the Galactic center from their infrared spectra, including data which we obtained ourselves with the Spitzer infrared space observatory.

• DFG Programme: Research Grants