Astronomers have used the combination of two powerful Maunakea telescopes (Subaru and Keck) to discover a nearby galaxy that has broken the record for having the lowest level of oxygen ever seen. In astronomy, elements heavier than hydrogen and helium (the two main elements created in the Big Bang) are called “metals”, and the earliest galaxies are expected to have very few metals like oxygen. The researchers measured the oxygen abundance of this particular galaxy, known as HSC J1631+4426, at less than 2 percent that of our Sun, suggesting that it is very young and only recently started making stars. Most galaxies in the present-day universe are already mature, making young galaxies extremely rare and hard to find. To comb through the vast amount of data and zero in on these young galaxies that are just beginning to form stars, the research team developed a new machine learning method, where they essentially “taught” a computer to pick out only galaxies in the early stage of formation. Oxygen-poor galaxies found today serve as analogs for galaxies born shortly after the Big Bang, thus helping us to better understand how galaxies formed and evolved in the early Universe.
Read more in the Subaru and Keck observatory press releases.