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

目前，在最近和即将到来的观测仪器的推动下，红外光谱范围享有前所未有的重要性。地面望远镜，特别是与自适应光学和积分场光谱学有关的望远镜，结合了最高的空间分辨率和近红外的高效率，而天基仪器则提供了更宽的波长范围。最令人感兴趣的是银河系中心，它被尘埃云遮挡住了，因此只能在红外波长下观察到。许多炽热的大质量恒星聚集在这个神秘的区域。然而，对具有强烈恒星风的恒星(特别是所谓的沃尔夫-瑞耶星)进行纯基于红外的光谱分析仍处于起步阶段。我们小组开发了这种恒星大气及其出射光谱的理论模型。这里提出的项目将在模拟和分析Wolf-Rayet恒星光谱时打开进入红外范围的通道。我们将在数值计算中仔细地合成红外光谱。由于红外光谱中可观察到的谱线数目有限，参数研究必须揭示红外限制分析的重要性和唯一性。这些方法应首先通过在可见光范围内也可接触到的恒星进行验证。随后，我们将分析靠近银河系中心的恒星的红外光谱，包括我们自己从斯皮策红外空间天文台获得的数据。

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.