Star cluster formation at various scales: from galaxies to giant molecular clouds

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 Time:  Thursday, December 27, 2018, 02:00pm
 Title:  Star cluster formation at various scales: from galaxies to giant molecular clouds
 Speaker:  Dr. Hui Li (MIT)



Over the past decades, the discovery of a large number of young massive clusters (YMCs) in the local Universe and giant clumps in high-z galaxies suggests that clustered star formation is the dominant star formation mode. Mass and energy feedback from these enormous clusters is inevitably responsible for shaping the properties of their host galaxies. To model star formation in a more realistic way, I implemented a novel prescription in cosmological hydrodynamic simulations by treating star clusters as a unit of star formation. I tested this algorithm by running a suite of cosmological simulations with unprecedented parsec-scale spatial resolution. I found that various observed properties of host galaxies and star clusters are reproduced. Interestingly, we find some of these properties can be used to calibrate the subgrid models in the simulations. We follow the orbits of all simulated star clusters, estimate the cluster mass loss due to tidal disruption, and for the first time, investigate the connection between YMCs formed at high-z and the globular clusters observed at present. In parallel, to study how giant molecular clouds (GMCs) collapse to form star clusters and how they are eventually disrupted by stellar feedback from massive stars, I performed a suite of high-resolution hydrodynamic simulations of individual GMCs with self-consistent star formation and momentum feedback. I find that the final star cluster mass depends strongly on the surface density of the cloud due to the force balancing between gravity and momentum feedback.

Hui Li received his B.S. and M.S. in astronomy and astrophysics from Nanjing University in 2009 and 2012. He then moved to the University of Michigan and obtained his Ph.D. in 2017 under the supervision of Prof. Oleg Gnedin. He joined MIT Kavli Institute for Astrophysics and Space Research in Oct. 2017 as a postdoctoral associate working with Prof. Mark Vogelsberger. Hui’s research focuses on studying the formation and evolution of young massive star clusters in a cosmological context using various theoretical and numerical tools. He is also working on other astrophysical problems, such as the tidal disruption of massive clusters in a realistic galactic environment, the connection between young massive clusters formed at high-z and globular clusters observed in the local universe, the diversity of Milky Way-sized galaxies, the effect of anisotropic thermal conduction on AGN feedback, the origin of gamma-ray emission from cosmic rays accelerated in supernova remnants and pulsar wind nebulae.

Host: Prof. Dandan Xu

Slides: 20181227-Li.pdf