Abstract

Contributed Talk - Splinter JungeAG

Tuesday, 10 September 2024, 14:31   (S25)

Investigation of the Interstellar Medium by Using the Light of Hot Subdwarf Stars

S. Weich, U. Heber, M. Dorsch, A. Irrgang
FAU Erlangen-Nürnberg

The interstellar medium (ISM), composed primarily of gas and dust, plays a crucial role in many astronomical observations by affecting starlight through interstellar extinction and reddening, as well as absorption. In my master's project, I leverage the light of hot subdwarf stars to probe the ISM structure, particularly in the Galactic halo. Hot subdwarf stars are ideal background sources for this purpose due to their simply shaped spectra, the lack of intrinsic Ca II and Na I lines (typical ISM lines found in the optical), and their susceptibility to interstellar reddening. My analysis methods involve collecting and analyzing optical spectra of these stars to determine their atmospheric parameters. These parameters are essential for modeling spectral energy distributions (SEDs) based on ultraviolet, optical, and infrared photometry, which provide information about interstellar dust and allow for the calculation of distances and stellar parameters when Gaia parallaxes are available. Additionally, I fit the ISM lines present in the stellar spectra with Voigt profiles to quantify the amount of interstellar gas causing these lines. Developing these analysis methods and extracting parameters describing interstellar gas and dust is the current state of my project. The aim of this work will be to finally use these parameters to test the relationship between interstellar gas and dust. Additionally, they offer the possibility to compile comprehensive gas and dust maps, showing the distribution of interstellar material across the entire sky. As a side-effect, my work will provide many new atmospheric and stellar parameters for hot subdwarf stars.