Title:  Unveiling the bulge formation in distant submillimeter-bright galaxies with ALMA and JWST

Speaker: 谈清华

Institute: 紫金山天文台

Host: 王俊峰

Time: 2025.3.13 周四 14:30

Location: 物理楼 552

Abstract:

The high angular resolution and unprecedented sensitivity of ALMA give us a unique opportunity to study the gas and dust distribution in distant galaxies. In this talk, I will present our recent study on the morphology of the submillimeter emission in a sample of over 100 submm-bright galaxies at z~1-4. Using visibility-based morphological analysis, we modeled the dust continuum emission, revealing surface brightness profiles and 3D structures that point to thick, triaxial systems with light profiles steeper than typical exponential disks. This suggests that most of these highly star-forming galaxies are intrinsically spherical rather than disk-shaped. Supported by simulations, our findings indicate that the main mechanism behind the formation of these spheroids could be the simultaneous action of cold gas accretion and galaxy interactions. This study presents the first robust observational evidence that spheroids can form directly through intense star formation in the cores of extremely luminous starburst galaxies, without involving major mergers. With JWST, we will gain a more comprehensive understanding of galaxy formation and evolution in the early Universe.

Bio:

Qinghua Tan is currently an associate researcher at Purple Mountain Observatory (PMO). She got her PhD at PMO under the supervision of Prof. Dr. Yu Gao, focusing on the molecular interstellar medium of massive star-forming galaxies. In 2012-2013, She visited CEA-Saclay as a joint PhD student and later returned as a visiting scholar in 2021-2022, working with Prof. Dr. Emanuele Daddi. Since 2015, she has been working at PMO. Her research interest focuses on millimeter and submillimeter observations to study star formation in galaxies and the morphological evolution of galaxies in the early Universe.

Related papers:

https://ui.adsabs.harvard.edu/abs/2024Natur.636...69T/abstract

https://ui.adsabs.harvard.edu/abs/2024A%26A...684A..23T/abstract