Using large-scale observational data from the James Webb Space Telescope (JWST), we investigated the abundance ratio of oxygen going back to 13.3 billion years ago, 500 million years after the universe was born. The results revealed that oxygen levels rapidly increased in galaxies during the first 500 million to 700 million years of the universe. This is an extremely important research result in elucidating the process by which oxygen, which is essential to the Earth and life, was created from the beginning of the universe to the present.
When the universe was born in the Big Bang, only light elements such as hydrogen, helium, and trace amounts of lithium existed. Heavier elements such as oxygen are synthesized through nuclear fusion reactions inside stars during subsequent star formation, and are dispersed into galaxies through supernova explosions and other events. By observing the gas contained in more distant galaxies, we can investigate the abundance ratio of oxygen in the past universe. Previous observations have shown that there was already an abundance of oxygen in galaxies in the universe about 2 billion years after the Big Bang (12 billion years ago). However, it has been extremely difficult to observe galaxies in the past, that is, galaxies in the distant universe, because the wavelengths of visible light emitted by galaxies extend into near-infrared rays due to the strong influence of cosmic expansion. .
A research team led by researchers from the National Astronomical Observatory of Japan and the University of Tokyo’s Institute for Cosmic Ray Research has discovered 138 distant galaxies that are older than 12 billion years, for which it has been almost impossible to study the abundance ratio of oxygen. We succeeded in measuring the abundance ratio of oxygen in galaxies. This research used observation data obtained from the near-infrared spectrometer of JWST, which just began scientific operations in 2022. As a result, it was revealed that galaxies from the present to 13.1 billion years ago had an amount of oxygen depending on the mass of the galaxy. However, on the other hand, it was found that six out of seven galaxies found in the universe from 13.1 billion to 13.3 billion years ago had a high probability of containing less than half the amount of oxygen present. Kimihiko Nakajima, a specially appointed assistant professor at the National Astronomical Observatory of Japan, who is at the center of the research team, said, “This suggests that during the first 500 million to 700 million years after the birth of the universe, the abundance ratio of oxygen in galaxies dramatically increased. “We found that the number of cases has increased,” he emphasizes.
Learn about the process by which oxygen was created and stored in galaxies from 13.8 billion years ago, when the universe was just beginning and there was no oxygen, to the current era, when there is abundant oxygen and life exists. , was not well understood. It has been shown that in the early universe, between 13.1 billion and 13.3 billion years ago, the abundance of oxygen rapidly increased to reach the current universe, making it more likely that life first appeared in the universe than previously expected. This suggests that it may have been earlier.
Detailed article
Capturing traces of rapid increase in oxygen in the early universe
Institute for Cosmic Ray Research, University of Tokyo
Supplementary information
Presenter
Wanghiko Nakajima (Specially Appointed Assistant Professor, National Astronomical Observatory of Japan, National Institutes of Natural Sciences) Masami Ouchi (Professor, National Astronomical Observatory of Japan, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Institute for Cosmic Ray Research, the University of Tokyo) Yuichi Harikane (Assistant Professor, Institute of Cosmic Ray Research, the University of Tokyo) Yoshiaki Ono (University of Tokyo) (Assistant Professor, Cosmic Ray Research Institute) Yuki Isobe (Doctoral student, Department of Physics, School of Science, The University of Tokyo) Koya Umeda (Doctoral student, Department of Astronomy, Graduate School of Science, The University of Tokyo) Masamune Oguri (Professor, Center for Advanced Science, Chiba University) Yechi Zhang (National Institutes of Natural Sciences, National Astronomical Observatory of Japan, Japan Society for the Promotion of Science Special Researcher)
Joint presentation organization
National Institute of Natural Science, National Astronomical Observatory, University of Tokyo
Published paper
Kimihiko Nakajima et al. “JWST Census for the Mass-Metallicity Star Formation Relations at z = 4-10 with Self-consistent Flux Calibration and Proper Metallicity Calibrators”, in The Astrophysical Journal Supplement Series, DOI: 10.3847/1538-4365/acd556
