ALMA detected the most distant oxygenstem 2

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) detected a clear signal from oxygen in a galaxy located 13.1 billion light-years away from us. This is the most distant oxygen ever detected. Oxygen in this galaxy seems to be ionized by a number of young giant stars, and this detection is a key step to understand the enigmatic "cosmic reionization" in the early history of the Universe. These observations have opened a new window to probe the early Universe with ALMA.