Promotionsvortrag Physik: „Design and Implementation of a Dual-Waveband Stellar Intensity Interferometer for H.E.S.S.“

Ankündigung des Promotionsvortrags von: Naomi Vogel

In order to comprehend fundamental properties of stars, such as their surface brightness distribu-tion and effective temperature, it is necessary to determine their angular diameter, as this infor-mation is instrumental in developing precise stellar atmosphere models. The angular diameter is often derived through high-angular resolution measurements, a process known as interferometry, which involves the combination of light from multiple telescopes.

The main focus of this talk is the method intensity interferometry. It entails the analysis of the arri-val times of photons - the correlation of intensity fluctuations - detected by separate telescopes.

First developed in the 1950s by Hanbury Brown and Twiss, this method has recently gained re-newed interest due to advances in high-time resolution detectors and large light-collecting tele-scopes. One such facility is the High Energy Stereoscopic System (H.E.S.S.) in Namibia, originally built for gamma-ray astronomy. This work presents the design and implementation of a stellar in-tensity interferometer for H.E.S.S., covering mechanical setup and the selection of suitable obser-vation targets.

The interferometer was then used in two observation campaigns in 2022 and 2023, successfully measuring the angular diameters of six bright B-type stars. In the second campaign, system up-grades enabled simultaneous dual-waveband observations and the inclusion of a third telescope. The resulting multi-wavelength measurements offer new insights into stellar properties.

(Vortrag auf Englisch)

Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.