Universität zu Köln

Hamedani Golshan, Roya ORCID: 0000-0003-1993-2302 (2025). High-mass star formation across the Large Magellanic Cloud. PhD thesis, Universität zu Köln.

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Abstract

Star formation is a fundamental process that shapes the evolution of galaxies, with high-mass (M > 8 M⊙) star formation playing a critical role as a major driver of energy input and chemical enrichment. Despite significant progress, the mechanisms governing (high-mass) star formation remain incompletely understood, particularly within the unique extra galactic environments of the Large Magellanic Cloud (LMC). The LMC provides a rare laboratory for studying high-mass star formation under distinct environmental conditions compared to our Galaxy, the Milky Way, including lower metallicity, enhanced ultraviolet (UV) radiation, reduced cosmic ionization rates, and large-scale dynamical interactions. These factors might influence key star- formation processes such as fragmentation, core mass distribution, clustering, chemical composition, and feedback mechanisms. Thus, studying these processes in the LMC offers critical insights into how environmental factors shape star formation across different galactic contexts. This thesis presents the first systematic survey of 20 massive young stellar objects in the LMC, selected from Spitzer and Herschel catalogs. The sample spans diverse physical and chemical conditions, evolutionary stages, and locations across the LMC, where metallicity gradients and varying levels of external feedback provide a statistically significant dataset for understanding star formation. Using high-resolution observations from ALMA, complemented by ATCA data and ancillary datasets from Herschel, Spitzer, and VISTA, this study explores the physical and chemical properties of star-forming regions. Among the main findings of this work, the high-angular resolution reveal diverse fragmentation and clustering patterns. Chemical properties exhibit a complex interplay with metallicity, deviating from linear scaling, and signatures of large-scale interactions and metallicity mixing emerge. The detection of filaments, outflows, and HII regions further confirms the dynamic feedback processes shaping gas morphology. This multiwavelength characterization of 20 star-forming regions advances our understanding of high-mass star formation in low-metallicity environments, emphasizing the influence of environmental diversity. By combining physical, chemical, and kinematic insights, this study provides a statistically robust foundation for future extra- galactic star formation research.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Hamedani Golshan, Roya UNSPECIFIED orcid.org/0000-0003-1993-2302 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-781763
Date:	2025
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics I
Subjects:	Physics
Uncontrolled Keywords:	Keywords Language Star formation (prestellar and protostellar cores, fillaments, outflows, etc.) English Large Magellanic Cloud English Astrochemistry English
Date of oral exam:	21 March 2025
Referee:	Name Academic Title Schilke, Peter Professor Eckart, Andreas Professor Löhnert, Ulrich Professor
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/78176