National Astronomical Observatory of Japan

A new-year’s message from the Director General, NAOJ

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As in the last year, the novel coronavirus COVID-19 has been wreaking havoc across the globe since the start of the new year, forcing us to confront the difficulty of implementing measures against viral infection while continuing research activities and telescope operations. We deeply appreciate the dedication of every health care and essential services worker, and hope this pandemic will end soon.

Since the beginning of the last year, people have communicated their concerns to the NAOJ Directorate about its decision-making process and communication with the various astronomy communities, and last December, the NAOJ-Community Communication Promotion Committee issued the “Mid-Term Report on the Advancement of Japanese Astronomy.” We are taking seriously every identified issue and suggested improvement in this report. Following the upcoming final report, we will work to ensure smooth communication not only within NAOJ, but also with our related communities.

As for astronomy in 2020, the Nobel Prize in Physics was awarded for theoretical and observational studies on black holes. The fact that physics laureates were selected from the field of astronomy for two consecutive years since 2019 is a testament to the remarkable development of this discipline. Among this time’s laureates, Reinhard Genzel and Andrea Ghez made long-term, high-resolution observations of the movement of stars near the center of our Milky Way Galaxy, proving that an invisible supermassive black hole lurks there.

Prior to their breakthroughs, a pioneering achievement was made with the Nobeyama 45-m Radio Telescope: the discovery of fast-moving gas near the center of galaxy NGC4258 by Naomasa Nakai (a researcher in NAOJ at that time) and his colleagues. Based on this discovery in 1992, Makoto Miyoshi (NAOJ) conducted high-resolution observations of this gas using the Very Long Baseline Array (VLBA) of the U.S.A., and in 1995 found that the gas is distributed in the form of a disk encircling the galactic center. These results suggested that something with an immense mass that cannot be explained by something like a star cluster exists at the galactic center, leading to the achievements that won this time’s Nobel Prize in Physics. The Nobel Foundation specifically mentioned Miyoshi by name in the prize citation and praised his pioneering work.

Research on supermassive black holes at the centers of galaxies also laid the foundation for the image of the black hole shadow in the elliptical galaxy M87 published in 2019. This breakthrough was achieved by the Event Horizon Telescope (EHT), a worldwide network of eight radio telescopes, in which the Japanese team led by researchers from Mizusawa VLBI Observatory made major contributions including research on image synthesis. The participation of ALMA, operated by NAOJ together with an international partnership, was also essential for the success of the EHT observations. In this way, it is no exaggeration to say that NAOJ has been at the world’s forefront of black hole research.

Another big topic in astronomy last year was Hayabusa2’s return to Earth on December 6. The RISE Project played a pivotal role in the operation, and analysis of data from Hayabusa2’s laser altimeter, a device vital for collecting samples from the asteroid Ryugu, contributing largely to this memorable mission. We anticipate that the collaboration in planetary exploration between NAOJ and the Institute of Space and Astronautical Science (ISAS) will feed into the Martian Moons eXploration (MMX) and the JASMINE projects, bridging the gap between exoplanet research and Solar System exploration.

As for the future, we are making continued efforts to build the Thirty Meter Telescope (TMT), a project that should advance the frontier of human knowledge by directly imaging Earth-like exoplanets to search for signs of extraterrestrial life.

Due to the delay in on-site construction, the activities in Japan have been slowed down to match the overall project. However, we are very grateful that domestic manufacturers continue to show their willingness to fully cooperate with the TMT Project. We are working to make the necessary preparations so that we can return to normal activities as soon as the on-site construction resumes.

In 2020, we made many important advances toward the realization of TMT. In May, the TMT International Observatory (TIO) submitted a design proposal for TMT to the National Science Foundation (NSF). Now this proposal will go through NSF’s project reviews, an environmental impact assessment, and the National Historic Preservation Act process, before being officially approved by NSF along with the subsequent budget process in the U.S. Congress.

Following the spread of the novel coronavirus, the Subaru Telescope had to suspend its operations and observations for two months from the end of March 2020, but the entire staff worked together to implement preventive measures and successfully resumed open-use observations on May 18. Since travel to and from Hawaiʻi remains restricted, we are promoting remote operation of the Subaru Telescope.

Even in such difficult times, Hyper Suprime-Cam (HSC) has yielded many scientific achievements. During collaborative observations with NASA’s interplanetary space probe, New Horizons, HSC discovered dozens of new Kuiper Belt objects, and these discoveries have facilitated the planning of future follow-up observations with New Horizons.

After more than 20 years since its completion, the Subaru Telescope is now showing signs of serious deterioration in various functions. Although we are taking measures with the support of MEXT, our tight budget situation is hindering the stable operation of the Subaru Telescope. In order to maintain the Subaru Telescope for many years to come, continued financial support is needed.

We have launched the “Subaru Telescope 2” project to fully exploit the Subaru Telescope’s wide field of view, aiming to produce world-leading scientific results for the next two decades. Three main pieces of equipment form the core of this project: HSC, PFS (Prime Focus Spectrograph), and ULTIMATE (Ultra-wide Laser Tomographic Imager and MOS with AO for Transcendent Exploration). The start-up operation of PFS in Hawaiʻi led by Kavli IPMU is getting serious now, and we are so excited about the preliminary observation run scheduled in 2021. In collaboration with TMT, the Subaru Telescope 2 should lead the world in the field of optical/infrared astronomy throughout the 2020s and 2030s.

As in previous years, ALMA produced significant results in 2020. The Band 1 receiver, which covers the lowest frequency band of ALMA, is in the production phase in cooperation with Taiwan, and a new spectrometer for the Atacama Compact Array (Morita Array), developed with the cooperation of the Republic of Korea, is in the pre-deployment preparation phase.

On the other hand, the operation of ALMA has been suspended since March 2020 following the spread of COVID-19 in Chile, but reactivation procedures have been underway since October. It is not an easy task to restart the large-scale observational facility while implementing preventive measures against the virus and safety measures for high-altitude operation, but the project team is working to resume observations as soon as possible.

We should not be complacent about the current success of ALMA, which is about to celebrate the 10th anniversary of its first scientific observations. Thus, we are now advancing the ALMA 2 project, aiming to upgrade the world’s most powerful telescope through collaboration between Japan, the U.S.A., and Europe by increasing its sensitivity, resolution, and simultaneously observable frequency bands. This project was selected in the MEXT Roadmap 2020 along with the Subaru Telescope 2 project. The spectrometer team of the Advanced Technology Center has successfully demonstrated a wide-bandwidth receiver that covers frequencies above 17 GHz, leading the world toward the ALMA 2 project. The ASTE 10-m radio telescope in Chile has also been forced to suspend operations due to the COVID-19 pandemic. However, in cooperation with the Advanced Technology Center and universities, the project team has advanced the development of the Band 8 receiver and the deployment of a new spectrometer, bringing us closer to realizing the ALMA 2 project. We expect that these new devices and collaboration with ALMA will usher in further developments.

The Large-scale Cryogenic Gravitational Wave Telescope KAGRA, constructed and operated in collaboration with the Institute for Cosmic Ray Research, University of Tokyo and the High Energy Accelerator Research Organization, collected its first scientific data last year. Due to the COVID-19 pandemic, KAGRA could not perform collaborative observations with LIGO in the U.S.A. and Virgo in Europe, which have suspended their third observation run. However, we expect that KAGRA will detect gravitational waves during the fourth observation run, which is scheduled for late 2022 or later. NAOJ with other partners developed quantum optics technology called, “frequency-dependent squeezed vacuum” for the interferometric gravitational wave antenna TAMA300 in Mitaka Campus. They demonstrated this technology in the practical frequency band (about 100 Hz) for the first time in the world. This technology can improve the sensitivity of gravitational wave telescopes. The day when KAGRA will lead gravitational wave astronomy is not far off.

Nobeyama Radio Observatory’s Nobeyama 45-m Radio Telescope has achieved numerous successes, including historical discoveries that led to the Nobel Prize. It launched a campaign to create “a map of where stars will soon be born in the constellation Orion.” Mizusawa VLBI Observatory has also been active, releasing results that determined the distance to the center of the Milky Way Galaxy and the galactic rotation velocity at the position of the Solar System with higher accuracy. This was the culmination of 20 years of Very Long Baseline Interferometry observations with VERA. VERA is expected to expand with the East Asian VLBI Network and produce further achievements in the future. Thanks to the leadership of the directors of both observatories, operational efficiency has been improving through measures such as switching to remote operation for open-use observations and moving to in-house maintenance. I would like to thank both directors for their efforts.

Turning to the satellite programs, Small-JASMINE (JAXA competitively selected small satellite No. 3) will be the first in the world to perform ultra-high-precision astrometry observations in the infrared. Small-JASMINE has matured through the addition of the exploration of terrestrial planets around low-temperature stars to its scientific goals and progress on technical studies. The Solar-observing Satellite project Solar-C (EUVST) has been selected at ISAS/JAXA as the 4th competitively selected small mission. This year will be an important year to advance this project, in cooperation with JAXA and overseas organizations. In addition, following the success of ultraviolet spectro-polarimetry observations by CLASP and CLASP2 and X-ray spectroscopic observations by FOXSI-3 all launched by NASA sounding rockets, the successor experiments are also scheduled to launch using NASA sounding rockets, CLASP 2.1 in 2021 and FOXSI-4 in 2024. The international joint balloon experiment SUNRISE-3 with participation by Japan, Europe, and the United States is scheduled to fly in 2022. The development of the onboard Sunrise Chromospheric Infrared spectroPolarimeter SCIP has reached its climax in the Advanced Technology Center. It is expected to achieve higher resolution and polarization accuracy than the solar observation satellite “Hinode.” This suite of sub-orbital missions shows NAOJ’s leadership role in solar physics from space, but 2021 will also be an important year as a prelude to NAOJ’s full-scale entry into space-based astronomy in the 2030s, not limited to just observing the Sun.

Researchers and citizens are working together to achieve astronomical results. The Public Relations Center and Subaru Telescope are jointly promoting a citizen astronomy project called “GALAXY CRUISE.” General citizens classify the shapes of colliding galaxies out of the vast amount of data obtained by HSC. As of December 1, 2020, there have been 5,779 people from 80 countries and regions who have participated, and the total number of galaxies classified has exceeded 950,000. Combining these results with machine learning is likely to produce a new leap in galaxy research.

The Spectrum Management Office of the Public Relations Center has entered the second year since its establishment. The fact that NAOJ established a specialized office to preserve the environment for astronomical observation is garnering attention. In addition to preserving the environment for radio observation, prevention and mitigation of light pollution have been added to its responsibilities. NAOJ’s Ishigakijima Astronomical Observatory observed the SpaceX Starlink satellites, which have been an issue since last year, in the visible to near-infrared region. These observations support SpaceX’s efforts to reduce light pollution.

The Japanese Virtual Observatory (JVO) of the Astronomy Data Center is actively publishing data from ALMA and the Subaru Telescope. During 2020, JVO offered 262 TB of data, with a total access count of approximately 12 million from 70 countries and regions around the world and approximately 9 TB of downloads, making a significant contribution to database astronomy.

The Advanced Technology Center (ATC) has been developing test parts for TMT/IRIS structural parts and working on mass production of corrugated horns for the ALMA Band 1 receivers. To make all these products, we use the newly introduced 5-axis machining center and metal 3D printer. Work on these parts will be completed in 2021. We expect that these machines will contribute to development and production of increasingly complex and sophisticated ground-based and space-based instruments. We look forward to new endeavors from NAOJ’s three centers.

In addition, the Division of Science is producing results through collaboration between observations, theory, and information technology; for example, the discovery of multiple new-born galaxies by applying new machine learning methods to large-scale data from the Subaru Telescope. ATERUI II (theoretical peak performance 3 Pflops) is a massive parallel supercomputer in the Center for Computational Astrophysics (CfCA). It has been operated stably for shared use. It also supports research using machine learning and artificial intelligence. Two study groups, SKA1 and ngVLA, were established last year. These study groups, together with the community, actively pursue investigations from both the science and technology points of view. The Japanese version of the SKA1 Science Book was revised, and we are preparing for the proceedings called, “ngVLA-J Memo Series.”

The 188-cm Reflector Telescope in Okayama, operated by Tokyo Institute of Technology, has continued surveying for exoplanets through remote operation during the spread of COVID-19. The 3.8 m Seimei Telescope at the Okayama Observatory of Kyoto University has been observing continuously throughout the pandemic due to the efforts of the everyone involved. Open use of the telescope, administrated by NAOJ, has been proceeding smoothly. The Optical and Infrared Synergetic Telescopes for Education and Research (OISTER), which is a network that performs collaborative observations using small and medium-sized telescopes owned by various universities in Japan, and the Japanese VLBI Network (JVN) are active in the fields of research and education. The Industry Liaison Office has been established with the aim of applying various technologies used in astronomy to improve the quality and safety of our daily lives. We are looking forward to the future activities of this office.

NAOJ is an inter-university research institute with the huge responsibility for Japanese astronomy in general. To support the astronomy community is one of the main reasons for NAOJ’s establishment. NAOJ will carry out its mission while carefully listening to the opinions of everyone inside and outside of NAOJ. NAOJ faces challenges head-on and works to overcome them by coordinating the full strength of the entire organization. We’d like to ask everyone, particularly the astronomy community, for their continued understanding and support.

January 5, 2021
Dr. Saku Tsuneta