News

2025

NOVEMBER 27, 2025 Press Release: Capturing the Universe on a Second Timescale - Mass Detection of Flash Events from Artificial Satellites and Space Debris -; A research team consisting of members from Tohoku University, the University of Tokyo, RIKEN, NTT, and Tokyo University of Science has conducted the world’s most sensitive “wide-field video observations” of the night sky using the wide-field camera Tomo-e Gozen at Kiso Observatory. As a result, the team detected more than 1,500 flash events lasting only 0.5 seconds. Most of these flashes were caused by reflections of sunlight from artificial satellites and space debris. The study revealed that such flashes occur as frequently as 10 million times per day across the whole sky. This finding highlights the significant impact that artificial objects have on searches for second-scale transient phenomena in visible light—an important step for future transient surveys.
AUGUST 7, 2025 Press Release: The galaxy was grainier than expected just after birth; A research team including members from the University of Toronto and the University of Tokyo has revealed that a faint, young galaxy, which existed about 900 million years after the Big Bang, exhibits a fragmented structure resembling a "bunch of grapes," composed of at least 15 compact star clusters. Despite this fragmented appearance, the galaxy as a whole displays smooth rotational motion of its gas. This structure was unexpected, as it deviates significantly from previous observations and numerical simulation predictions. The galaxy studied is representative of typical galaxies from that era, suggesting that similar structures may be hidden in many others. These findings could lead to a significant revision of our understanding of galaxy formation in the early universe.
July 1, 2025 Press Release: Galaxies Grow Stars with Gas from Outside; A research group led by Maki Nagata, a graduate student in the Department of Astronomy at the Graduate School of Science, The University of Tokyo, has discovered ten molecular clouds in the nearby barred spiral galaxy M83 that are moving at velocities significantly different from the galaxy’s disk rotation. This study systematically investigates high-velocity clouds (HVCs) composed of molecular gas, which had not previously been observed flowing into the galactic disk in nearby galaxies. Detecting the inflow of such high-density gas from outside the galaxy is expected to provide key insights into how galaxies sustain star formation over long timescales.
May 22, 2025 Press Release: A fierce storm in a giant barred spiral galaxy 11 billion years ago; ALMA has obtained detailed images of the gas distribution and motion in the barred spiral structure of a monster galaxy. The results reveal that this galaxy, which existed in the early universe, looks very similar to barred spiral galaxies in the present-day universe, but the gas within its barred structure is blowing violently and causing intense star formation. This is an important research result that adds new knowledge to the history of galaxy growth and evolution.
May 13, 2025 News: Japan–Chile Summit Discusses Cooperation in Space and Astronomy; On May 11, 2025, Prime Minister Shigeru Ishiba held a summit meeting lasting approximately 70 minutes with President Gabriel Boric Font of the Republic of Chile, who was visiting Japan as a guest for Expo 2025 Osaka, Kansai. The two leaders shared a sense of cultural closeness, particularly through their mutual interest in Japanese literature. Notably, they expressed hopes for further collaboration in the fields of space and astronomy, citing the commemorative ceremony marking the completion of the University of Tokyo Atacama Observatory (TAO) telescope site. Click here for the TAO webpage regarding this news.

Photo: quoted from the webpage of Ministry of Foreign Affairs of Japan
Mar 24, 2025 News: Associate Professor Shigeyuki Sako has been awarded the Shoichiro Yoshida Memorial Nikon Astronomy Achievement Award; Associate Professor Shigeyuki Sako of the Institute of Astronomy has been awarded the 2024 Shoichiro Yoshida Memorial Nikon Astronomy Achievement Award. This prestigious award, presented annually by the Japan Astronomical Foundation, honors researchers who have made remarkable contributions to the advancement of astronomical observation methods, particularly those involved in the development of cutting-edge astronomical instruments. The system, named "Tomo-e Gozen" — after the legendary warrior associated with Kiso — continues to operate at Kiso Observatory, capturing an impressive average of 8 terabytes of data per night. This unprecedented data stream has significantly contributed to the advancement of time-domain astronomy in Japan.
Feb 12, 2025 News: Big Data Science in the Beautiful Night Sky of Kiso; The ceremony celebrating the 50th anniversary of Kiso Observatory was held on December 8, 2024, at the Cultural Hall of Kiso Cultural Park in Kiso County, Nagano Prefecture, with many distinguished guests in attendance. Kiso Observatory was established in 1974 and has since fostered many astronomers and made significant astronomical contributions. As the only domestic observatory operated by the University of Tokyo, it has been dedicated to research and education, and in recent years has also focused on social engagement and regional collaboration.