National Astronomical Observatory of JapanCosmic History / Observational Cosmology Group
ーQuest for the Unknown Early Universeー
Research
Uncovering the Early Universe to the Present Universe by Multi-Wavelength Observations
This research group explores formation of galaxies and supermassive blackholes over the cosmic history with a strong focus on the early epoch of the universe. Having an emphasis on optical near-infrared observations such with Subaru Telescope, we are conducting multi-wavelength observational studies with various large facilities including the ALMA radio telescope. Here is the list of our research topics and the observational facilities to be used.
Early galaxies and the supermassive blackholes (Hubble Space Telescope, ALMA, Spitzer Space Telescope etc.)
Evolution of large scale structures and the cosmic reionization (Subaru Telescope, Hobby-Eberly Telescope Dark Energy Experiment HETDEX, Mileura Wide-Field Array MWA etc.)
Explorations for the cosmic living fossils of nearby early galaxy/supermassive blackholes (Subaru Telescope, Keck Telescope, SDSS, Chandra X-ray Observatory etc.)
Some of the studies above are empowered by the information technology of artificial intelligence including machine learning with and without a training data set. (For example, in the study of #3, we have successfully selected an early galaxy out of about one million objects detected in the Subaru Hyper Suprime-Cam data.) We also compare our observational results with our cosmology model calculations and the other groups’ numerical simulations, uncovering physical origins behind the observational results. (For examples, the observed cosmic star-formation history is explained by the combination of the cosmic expansion and the growth of cosmic structures by gravity. Our discovery of the 10-kpc scale giant carbon gas halos of early galaxies cannot be explained by the state-of-the-art numerical simulations, suggestive of strong outflows that have not been predicted by theoretical models.)
In the coming 5 years, we will have exciting endeavors to witness the early stage of galaxy formation in the very distant universe with NASA’s James Webb Space Telescope (JWST) to be launched in a couple of years and to unveil the early large-scale structures of the universe under the process of the cosmic reionization with Subaru Prime-Focus Spectrograph (PFS). After the 5 years, we will further expand the scope of our studies with the forthcoming NASA’s WFIRST mission and Thirty Meter Telescope (TMT) program that is the on-going effort here at NAOJ.
