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Title: Relating Morphological Asymmetry and Large-scale Environment 

          to Star formation and Gas Accretion in Galaxies

Speaker: Dr. Hassen Yesuf (Kavali IPMU-KIAA)

Date&Time: 2022-12-07, 10:30 AM

Location: 과학관 638 (Science Hall, 638)

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Abstract
I will give an overview of my recent and current work on star formation in local galaxies. Gas accretion and environment are important drivers of galaxy properties. Gas inflows, while challenging to directly observe, are predicted to regulate the star formation rate (SFR) and metal contents of galaxies. I study the multivariate association among several observable galaxy properties to distinguish the main drivers of SFRs and test our theoretical understanding of galaxy evolution. In my recent work, I find that the amount of star formation in galaxies is related to morphological asymmetry and central mass concentration. Star-forming galaxies (SFGs) with higher asymmetry and stronger bulges have higher SFR at a given M*. The asymmetry reflects both irregular spiral arms and lopsidedness in seemingly isolated galaxies and structural perturbations by galaxy interactions or mergers. Both merger and direct gas accretions can induce asymmetries, drive gas to the center, elevate SFR, and build a central concentration of stars. The multiscale environments are also correlated with SFR, in a sense that star-forming galaxies with enhanced SFR than average, at a fixed stellar mass, live in lower-density environments, while SFGs with lower SFR than average live in slightly higher-density environments. However, structure explains the SFR diversity of SFGs better.