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Taysun Kimm's group works on how stars form in galaxies and drive strong outflows, using radiation-hydrodynamics simulations with adapative mesh refinement. We are also interested in various topics, including reionization of the Universe, escape of LyC and LyA photons from galaxies, RAM pressure stripping in clusters, formation of globular clusters, and the origin of the giant Lya nebulae etc.


Latest news

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A new probe of turbulent structures: LyC-LyA

The upcoming large telescope programmes will allow us to study details of kinematic properties of galaxies. In particular, the propagation of UV radiation will potentially be one of the most useful probes of galaxy evolution: the escape of LyC photons tells us what fraction of a galaxy is covered by optically thick neutral hydrogen, whereas the line profile of LyA photons reflects gas kinematics. Thus, understanding both properties simulataneously will be the next step forward for galaxy formation theory (Kimm et al. 2019, MNRAS).
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Lya pressure is a strong feedback mechanism

Non-thermal pressure due to resonantly scattering Lyman alpha photons is a form of stellar feedback that has been neglected in galactic simulations. By carrying out a series of RHD simulations, we find that Lya pressure can impart a significant amount of radial momentum in the early phase of star formation. This leads to the disruption of star-forming clouds, which modulates clustered, bursty star formation episodes. As a result, the number of star cluster formed and survived is significantly reduced in the model with the strong radiation feedback (Kimm et al. 2018).
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Binaries accelerate reionization

SPHINX is the first radiation-hydrodynamic simulations that simulataneously capture large-scale reionization and the escape of ionizing radiation from thousands of galaxies. In this work, we find that the interactions in a binary system have a signifcant impact on the timing of reionization. We will use the SPHINX simulations to study the back-reaction of suppressed galaxy growth via reionization and to predict the observational properties of extreme-redshift galaxies, which will become increasingly visible to us when the JWST comes online (Rosdahl et al. 2018)..
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Magnetic field tracer algorithm

We develop a magnetic field tracer algorithm for cosmological simulations that can track the origin and evolution of different components of the magnetic field. We find that primordial magnetic fields dominate the majority of the volume of the simulations, whereas SN-injected magnetic fields are confined to galaxies and the vicinity of their dark matter haloes by z=6. These simulations represent a first demonstration of the magnetic field tracer algorithm which will be an important tool for future cosmological MHD simulations (Katz et al. 2018)