2026年第5次学术报告: Star formation in low-metallicity environments of the Milky Way: from clouds to cores
摘要：
The outer Galaxy provides a unique opportunity to study the impact of metallicity on star formation at a spatial resolution sufficient to resolve individual clumps and cores. The metallicity declines as a function of Galactocentric radius and is in between that of the Magellanic Clouds and the inner Galactic disk. The reduced abundances of dust and molecules heavier than H2 affect the overall gas and dust cooling budget. The average flux of cosmic rays and the ultraviolet radiation field strengths are lower, but both high energy particles and radiation penetrate deeper into the clouds due to less shielding. The differences in environmental conditions and the high fraction of atomic-to-molecular gas are expected to lower the star formation rate per surface area. Together with the well studied, higher-metallicity local molecular clouds, the clouds in the outer Milky Way offer a unique opportunity to study the impact of metallicity on star formation.
In this talk, I will review recent observational efforts in the outer Galaxy from physical scales from clouds to cores. On cloud scales, I will present research highlights from the APEX 'Outer Galaxy High Resolution Survey' (OGHReS), probing CO emission in the entire 3rd quadrant of the Galaxy with unprecedented detail, and from complementary surveys using denser gas tracers (e.g. HCN, HCO+) and atomic carbon. Next, I will discuss the gradients of molecular abundances in star-forming clumps across the Galactic disk, indicating the underlying role of metallicity. On core scales, I will discuss studies of outflow activity in the outer Galaxy using JWST and ALMA/NOEMA. I will conclude with emphasizing key differences between the outer Galaxy with the Solar neighborhood, and links with extragalactic star formation.
报告人简介：
Dr. Agata Karska is an assistant professor and the leader of the Molecular Astrophysics Group at the Institute of Advanced Studies at Nicolaus Copernicus University in Toruń, Poland. She is interested in the impact of metallicity on star formation on Galactic scales, as well as the radiative and mechanical feedback from low- to high-mass protostars on clump/core scales. She earned her Ph.D. from Leiden Observatory in 2014 under the guidance of E. F. van Dishoeck and G. Herczeg, after which she pursued her academic career in Poland. From 2022 to 2025, she took an extended sabbatical at the Max Planck Institute for Radio Astronomy in Bonn, Germany, where she developed the multi-species follow-up of the 'Outer Galaxy High Resolution Survey' (OGHReS), the large APEX program in CO 2-1 covering the sparsely studied 3rd quadrant of the Galaxy.
报告邀请人：李小虎
报告时间：2026年4月7日下午16:00
报告地点：台本部南楼210会议室