About US
Background
Our research aims to observarionally elucidate the fundamental question of how stars, galaxies, and supermassive black holes formed, how clusters of galaxies grew in the early universe, and how the present hierarchical structure was formed. Subaru Telescope has been conducting the world’s most advanced observations by utilizing its excellent light-collecting power and high-performance detectors. In particular, Hyper Suprime-Cam (HSC), installed at the prime focus, boasts a unprecedented wide field of view and high sensitivity. The Japan-led HSC survey has had a major impact on the research community by revealing cosmic structure and galaxy formation from the cosmic reionization period to the present.
Currently, astronomical observation instruments are undergoing a major transformation. Ground-based telescopes are evolving from 8-meter class to 30-meter class super-massive telescopes, and the 8.4-meter Rubin telescope in the United States is being planned as a dedicated survey telescope that will efficiently generate large-scale time series data. In addition, the generation of space telescopes have shifted from Hubble to the 6.5-meter James Webb Space Telescope (JWST), which was launched in 2021, and the world’s observation strategy has now entered a new era.
Objective -The horizon we aim for –
Along with this background, in order for Japan to further lead the world while maintaining the strong momentum of the HSC Survey, it is important to connect the scientific results and knowledge of technological development for the next-generation telescope under international collaborations.
In order to further develop the knowledge for multiple view points, we have set the following five goals.
- Capturing the time changes of cosmic phenomena using time-series data
- Observing the distant universe to understand the formation of the first stars and evolution of galaxies in the very early universe.
- Understanding the structure formation of the Universe starting from the high redshift to the present, continuously.
- Understanding the physical properties of distant objects in detail through spectroscopic observations
- Obtaining powerful statistics by unleashing the large scale and high precision observations of HSC
Methods
To achieve the goals outlined above, we will pursue parallel efforts: one based on developing instruments for the Subaru Telescope and the other aimed at contributing to external observation facilities. In addition, we will promote critical theoretical research necessary for interpreting the results of these observations. The ULTIMATE project involves equipping the Subaru Telescope with a new adaptive optics system, enabling it to achieve image resolution comparable to that of space telescopes. By incorporating medium-band filters (HSC-MB) into the Subaru HSC (Hyper Suprime-Cam), we will conduct the world’s first precise redshift (distance) measurements of extremely faint galaxies. This will facilitate a continuous investigation of galaxy evolution across cosmic scales and make a significant impact on cosmological analyses using gravitational lensing surveys by telescopes like Rubin and Roman.
Additionally, MORFEO, an adaptive optics instrument for Europe’s Extremely Large Telescope (ELT), will benefit from the integration of unique Japanese technologies, enabling Japan to secure observation time on the ELT. Through the development of these relatively small-scale instruments, we aim to open numerous opportunities to tackle cutting-edge research challenges. This contributes to the advancement of the entire astronomy community while serving as an efficient strategy for nurturing young researchers who can thrive on the global stage.
Scientific Goals
The universe exhibits a hierarchical structure, including stars, galaxies, galaxy clusters, and large-scale structures. However, there have been only few systematic studies based on homogeneous, large-scale datasets. Recently, advances of data-driven science have made it increasingly possible to achieve to make a unified model of the formation and evolution of cosmological structures, with initiatives led by instruments such as Rubin, JWST, and ELT. In particular, precise galaxy distance estimates using HSC-MB and the discovery of proto-clusters and massive galaxies in combination with ULTIMATE are highly anticipated. These efforts will enable us to describe the evolution of large-scale structures in the early universe, potentially imposing new constraints on hierarchical structure formation theories.
To address fundamental questions such as the formation of the first galaxies, cosmic reionization, the co-evolution of supermassive black holes and galaxies, and the birth and evolution of massive galaxies, Japan will leverage its unique technologies to develop MORFEO, an adaptive optics system for the world’s first 39-meter Extremely Large Telescope (ELT). Cutting-edge research using MORFEO is set to begin in 2028. Furthermore, these studies will be advanced with the Thirty Meter Telescope (TMT), scheduled for 2032, employing cosmological simulations to deepen the physical understanding of galaxy formation and black hole evolution.
For more detailed research information, please visit this page.
Collaborative Research Structure
Our research team is led by Satoshi Miyazaki, the Principal Investigator (PI) of the HSC survey, and consists of 10 co-investigators along with approximately 30 graduate students and early-career researchers. The co-investigators include experienced members of the HSC survey and core members of the Subaru Telescope, bringing together experts in observational astronomy and cosmology.
Through this project, we will recruit early-career researchers from across Japan via the M3eX program to promote international collaborative research. In particular, we plan to send young researchers to the University of Arizona, where they will conduct research using JWST data and share observational data obtained with HSC’s intermediate-band filters. At Princeton University, we will integrate early-career researchers into the Rubin project to foster joint research. Additionally, at the Center for Computational Astrophysics (CCA) in New York City, we will collaborate on the development of numerical simulations and data analysis tools.
With Italy’s INAF, we will participate in the development of the MORFEO adaptive optics system for the Extremely Large Telescope (ELT) as part of an international science team. Furthermore, in collaboration with the Australian National University (ANU), we will work towards equipping the Subaru Telescope with ground-layer adaptive optics (GLAO) and train early-career researchers in cutting-edge adaptive optics technology. This will strengthen Japan-Australia collaboration and maximize scientific outcomes with ULTIMATE.
For more details on research assignments and placements, please visit this page.
Young Researcher Education Plan
We plan to send early-career researchers to institutions in the United States (Arizona, Princeton, CCA), Europe (INAF, MPI, DAWN, ESO), and Australia (ANU, Swinburne). At the University of Arizona, they will focus on cosmology research, while at Princeton and CCA, they will engage in theoretical studies. At INAF and ANU, they will work on technological development. To ensure a productive start of their collaborative research, we will arrange thorough online preparations with local researchers beforehand, and provide logistical support during their stay. Additionally, project leaders and co-investigators will make regular visits to these institutions to facilitate collaborations and strengthen these research exchanges.
Currently, less than 10% of our researchers have experience with long-term stays abroad, while 30% have participated in short-term visits. International dispatch programs have declined due to the impact of COVID-19; however, more than 70% of researchers have expressed interest in long-term stays, confirming the high demand for such opportunities. Through our unique M3eX program, senior researchers will serve as mentors for early-career researchers, and we will establish a support system among young researchers themselves. From the third year onward, we will expand the program nationwide to further promote international collaborative research.
We will also plan to organize special sessions at astronomical society meetings and host international conferences to enhance information exchange and networking. Through these initiatives, we aim to increase the rate of researchers with long-term international experience to over 50% within five years, fostering a sustainable trend toward globalization.
For details on past research assignments for early-career researchers, please visit this page.