The old Milky Way: a holistic approach for the accurate analysis of metal-poor stars

• Applicant: Professor Dr. Norbert Christlieb
• Subject Area: Astrophysics and Astronomy
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 525711926

Metal-poor stars conserve in their atmospheres a fossil record of the nucleosynthesis processes that occured in the early Universe. Therefore, these old stars provide us with information on the properties of the first generations of stars (such as their mass distribution), as well as the early chemical enrichment history of the Galaxy. The aim of this project is to conduct a homogenous stellar parameter determination and abundance analysis of all currently-available high-resolution spectra of metal-poor stars, as well as the several million spectra to be acquired with the 4MOST multi-object spectrograph, using a new, holistic approach. This approach can be applied to spectra obtained with different instruments, irrespective of the resolving power, and return results that are on a single, consistent scale, which is crucial for the scientific exploitation of these datasets. We will develop a data analysis system that combines the use of spectroscopic, photometric, spectrophotometric, asteroseismic, interferometric, and astrometric data with state-of-the-art models. Multiple analysis methods will be implemented and cross-calibrated, creating a general data analysis system that delivers accurate results even when not all types of input data are available. The project is also of fundamental importance for the preparation of the exploitation of the data to be collected with the high-efficiency, near-ultraviolet (near-UV) spectrograph CUBES, that is planned to be mounted at one of the 8m-telescopes of the European Southern Observatory in Chile in 2028. Due to its about five times higher efficiency in the near-UV compared to the currently operational high-resolution spectrograph UVES, and its high resolving power (i.e., R = 20,000), CUBES will allow to accurately measure the abundances of elements that have their strongest absorption lines in that spectral region, such as many neutron-capture elements.This project will provide the framework as well as key support of the participation of the Polish and German partners in the two consortia who are developing CUBES and 4MOST.

• DFG Programme: Research Grants
• International Connection: Poland
• Cooperation Partner: Privatdozent Dr. Rodolfo Smiljanic