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Discover the Oldest Spiral Galaxy 12.4 billion Years Ago, The National Astronomical Observatory of Japan

Research groups such as the National Astronomical Observatory of Japan have announced that they have discovered a galaxy with a spiral structure 12.4 billion years ago, which is the oldest in the history of observation. The result of the ALMA telescope in Chile, South America, was found only 1.4 billion years after the birth of the universe 13.8 billion years ago, which will lead to the elucidation of the mechanism by which galaxies of various shapes exist in the universe.

In the present universe, spiral galaxies occupy about 70% of galaxies, including the Milky Way galaxy (Galaxy system) where the solar system is located. However, it is rare to go back in time, and only a few have been found that are more than 10 billion years old, including the one that was reported in 2019 and was considered to be the oldest 11.4 billion years ago. It has become a matter of interest when spiral galaxies began to be created in the history of the universe.

Therefore, the research group paid attention to “BRI1335-0417” in Virgo, which is 12.4 billion light-years away, among the galaxies observed by the ALMA telescope in 2018. We analyzed the data of carbon ions contained in the gas that is the material of the star. As a result, I discovered a bright and cohesive central part and a structure in which the two arms protruding from both ends swirl. The bulge in the center called the bulge and the movement of gas was similar in characteristics to the spiral galaxy.

Its mass is equivalent to that of the Milky Way, which is estimated to be 60 billion times that of the Sun. Takashi Tsukui, a doctoral student at the Graduate University for Advanced Studies in the research group, points out that “Galaxy that existed in the past is huge considering the possibility that substances will gather and evolve more and more in the future.”

The mechanism by which a spiral galaxy was formed in the early universe is called a mystery. Professor Satoru Iguchi (Radio Astronomy) of the National Astronomical Observatory of Japan and the Graduate University for Advanced Studies said, “Until now, I had the feeling that swirls could take time and be done later. This time, it was only 1 billion years from 11.4 billion years ago. It seems to have only been traced back, but it is very interesting to discover it near the birth of the galaxy, before the peak when the stars are actively formed and the structure of the galaxy is completed. It is important for considering the scenario of galaxy formation. It raised a problem. We need to make more observations. ”

The solar system is located in the spiral arm of the Milky Way galaxy, and clarifying the origin of the spiral is also a clue to the mystery of the birth of the solar system.

The ALMA telescope is a radio telescope that was built in Chile at an altitude of 5,000 meters and started observation in 2011. Operated by Japan, the United States, and Europe. It uses the technology of an “interferometer” that links 66 parabolic antennas into one giant telescope. It captures millimeter waves and submillimeter waves emitted from gas and dust with high sensitivity and high resolution and approaches the mystery of the birth and evolution of stars and galaxies.

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