Formation of massive galaxies in the early Universe and their multi-wavelength radiative properties
矢島 秀伸（筑波大学）/Hidenobu Yajima (University of Tsukuba)
Recent observations have successfully detected UV or infrared fluxes from galaxies at the epoch of reionization. However, the relation between the radiative properties and galaxy evolution has not been understood yet. Combining cosmological hydrodynamics simulations and radiative transfer calculations, we study the formation mechanism of galaxies and the origin of their radiative properties. We find that most of gas and dust are evacuated from star-forming regions due to supernova feedback. We show that galactic outflow allows UV photons to escape from galaxies. As halo mass increases, star- forming regions are covered by dusty gas, resulting in the formation of infrared bright galaxies. In my talk, we also show galaxy evolution in protocluster regions where many massive galaxies can form even in the early Universe. We show that massive dusty galaxies form along large-scale filamentary structure in the protocluster regions and the cosmic filaments emit Lyman-alpha cooling radiation.
Using stellar dynamics to connect the star formation and multi-message observations
Long Wang（Department of Astronomy）
Few-body dynamics plays an important role in the evolution of star clusters. Stars can escape the birth place after strong encounters with binaries. Perturbed binaries can merge to become more massive stars. Such few-body interactions also influence the energy flux of the stellar systems and determine the morphology and survival timescale of the clusters. I will show two examples how few-body dynamics can affect the feedback of star formation. This is especially related to the multiple stellar populations observed in the young star clusters like Orion Nebula Cluster and old globular clusters. On the other hand, the stellar-mass black hole is not only the progenitors of gravitational waves (GWs), but can significantly affect the long-term evolution of star clusters. Thus, by using stellar dynamics, we may construct a bridge to connect the initial mass function, primordial binaries and triples of young and old star clusters to the present observations from ALMA, Gaia and GW detectors.
hongo-astrotalks (at-sign) astron.s.u-tokyo.ac.jp