Title: Deconstruction of Galaxies: Unveiling Disks, Bulges, and Stellar Halos 

Speaker: Min Du 

 
Abstract: With the rapid development of large-scale galaxy cosmological simulations, combined with observational data, we have a great opportunity to accurately understand the structure of galaxies and their formation mechanisms. In a series of studies, based on unsupervised machine learning algorithms, we have developed a precise, efficient, and minimally intrusive method that can extract the intrinsic structures of simulated galaxies from the kinematic phase space. By applying this method to galaxies in the IllustrisTNG simulations, we have defined the structures of galaxy disks, bulges, and stellar halos with precision, and extensively investigated the formation processes of different galaxy structures from both internal and external mechanisms. In particular, (1) from the perspective of intrinsic mechanisms, we can clearly understand the formation process of disk structures and the origin of the mass-size relation of galaxies; (2) we point out that there is a serious conceptual confusion between the morphological decomposition of bulges and stellar halos, with the latter being a structure primarily generated by external mechanisms, e.g., mergers. Furthermore, we explore the impacts of specific physical mechanisms on different galaxy structures through the development of high-precision N-body + hydro simulations. 

References： 

https://ui.adsabs.harvard.edu/abs/2022ApJ...937L..18D/abstract 

https://ui.adsabs.harvard.edu/abs/2021ApJ...919..135D/abstract 

https://ui.adsabs.harvard.edu/abs/2020ApJ...895..139D/abstract 

 
Bio: Dr. Min Du obtained his Ph.D. in Astrophysics from the Shanghai Astronomical Observatory in 2017 and was awarded the "中国科学院院长特别奖." From 2017 to 2021, he worked as a postdoctoral fellow at Peking University, supported by the "博士后创新人才计划." Since September 2021, he has been serving as a Ph.D. supervisor and associate professor at Xiamen University.  

Min Du's research interests include galaxy formation and evolution, galaxy structures, N-body + hydrodynamic numerical simulations, and galaxy dynamics. Particularly, from a dynamical perspective, he proposed for the first time the co-evolution of small-scale bars-bulges-black holes in galaxies (Du+2017, Guo, Du+2020; Li, Du+2023). He also used N-body + hydrodynamic simulations for the first time to generate compact galaxies successfully (Du+2021). In recent works, he advanced the galaxy deconstruction field that is a powerful tool to unveil the formation and evolution of galaxies and their structures (Du+, 2019, 2021, 2022). 

Time: 14:00-15:00PM, 20/Mar, Wednesday 

Venue: Room 508 (large seminar room), Department of Astronomy 

You can also access the colloquium via :

https://www.koushare.com/homepage/329883