Colloquium on Mar. 19, 2026

Galaxy Formation in the Big Picture of the Cosmic Ecosystem

Speaker: Enci Wang (USTC)

Venue: SWIFAR Building 2111

Time: 16:00 PM, Thursday, Mar. 19, 2026

Abstract:

Star-forming galaxies continuously accrete gas from their surrounding environment over cosmic time, while stellar feedback simultaneously drives gas outflows and enriches the interstellar and intergalactic medium. The interplay between gas inflow, outflow, and star formation therefore plays a central role in shaping the formation and evolution of galaxies, as well as the key observational relations associated with them. From this perspective, the gas-regulator model can explain a wide range of observed galaxy scaling relations, including the existence and scatter of the star-forming main sequence, the mass–metallicity relation and its dependence on SFR and galaxy size, as well as the HI scaling relations, all arising from time-varying gas inflow during galaxy evolution. In addition, based on the ecosystem of galaxies, we construct a leaky accretion-disk model to describe the formation of gaseous disks in galaxies. This model quantitatively reproduces the radial gradients of gas-phase metallicity and further suggests that the exponential structure of star-forming disks originates from viscous processes driven by magneto-rotational instability. Although I gave a talk here three years ago, this time I will focus on recent developments and observational results.