Computer simulations are one of the major methodologies that astronomers nowadays adopt to investigate multiscale phenomena and physical processes in the cosmos. We mainly use hydrodynamic simulations, which often additionally include various subtle physical processes, e.g., magnetic fields, cosmic rays, viscosity, thermal conduction, radiation, general relativity, etc. Currently, our research topics include the growth of supermassive black holes in the early Universe, accretion flows, AGN outflows, AGN feedback, the circumgalactic medium, the intracluster medium, stellar feedback, galaxy evolution, etc.
Fig. 1: Predicted X-ray 1.5 keV surface brightness map in a representative hydrodynamic simulation of the forward-shock model of the Fermi bubbles in the Milky Way (Zhang & Guo 2020). The dotted line delimits the observed Fermi bubbles in gamma rays.
Ongoing Collaborations
Feng Yuan and Luis Ho collaborate on theoretical and observational studies of stellar and AGN feedback in galaxies and the role that they play in regulating star formation and ISM properties. Building on their expertise in black hole accretion, AGN physics, and galaxy astrophysics, they incorporate the latest developments in the physics of radiation and wind from black hole accretion flows at both cold and hot accretion modes into state-of-the-art numerical simulations of realistic galaxy models. The simulation is based on the MACER code. It focuses on the galactic scale, with the inner and outer boundary of the simulation being 10 times smaller than the Bondi radius and 250 kpc, respectively. The highest resolution is as high as 0.2 pc. The latest developments will consider the cosmological inflow taken from large scale cosmology simulations and more physics such as dust and cosmic ray.
Examples of their joint research include:
Li, Y.-P., Yuan, F., Mo, H. J., Yoon, D., Gan, Z.-M., Ho, L. C., et al. 2018, ApJ, 866, 70: Stellar and AGN Feedback in Isolated Early-type Galaxies: The Role in Regulating Star Formation and ISM Properties
Yuan, F., Yoon, D., Li, Y.-P, Gan, Z.-M., Ho, L. C., & Guo, F. 2018, ApJ, 857, 121. Active Galactic Nuclei Feedback in an Elliptical Galaxy with the Most Updated AGN Physics. I. Low-Angular Momentum Case
Xie, F.-G., Yuan, F., & Ho, L. C. 2017, ApJ, 844, 42: Radiative Heating in the Kinetic Mode of AGN Feedback