Lunch talk on May. 12, 2025

The Regulation of Galaxy Ecosystems in the Local Universe: Star Formation, ISM, and Quenching

Speaker: Chengpeng Zhang (KASI/Yonsei University)

Venue: SWIFAR Building 2111

Time: 12:45 PM, Monday, May. 12, 2025

Abstract: 

Galaxies in the local universe can be viewed as complex ecosystems where energy flows and matter cycles are regulated through internal processes and environmental effects. Investigating the ISM, star formation, and quenching mechanisms is essential for a comprehensive understanding of the regulation and evolution of galaxy ecosystems. In this talk, I will highlight our statistical results derived from extensive multi-wavelength surveys of local galaxies. Our analysis reveals that central disk galaxies with star formation rates significantly below the star-forming main sequence unexpectedly possess HI gas reservoirs comparable to those of star-forming galaxies, but exhibit significantly lower molecular gas content and star formation efficiency. We further demonstrate that quenching in these central disk galaxies is closely linked to bulge growth, bar-induced activities, and feedback from low-luminosity AGN. These results lead to a coherent picture of how internal “mass quenching” operates. Additionally, we find that the residual HI gas content provides a robust diagnostic for distinguishing between internal-driven and environmentally-driven quenching channels in satellite galaxies. Finally, I will present our latest insights into the star formation law, derived from studies of dust properties of the local galaxy population.

Report PPT:  SWIFAR_Chengpeng Zhang.pdf