Astronomers have announced that they have detected molecular oxygen in a galaxy that’s about half a billion light-years away from our galaxy. This is an important discovery because it’s only the third time astronomers have detected molecular oxygen outside of our solar system, and the first time it has been detected outside the Milky Way. Oxygen is believed to be a very abundant element in the universe and is the third most abundant element behind hydrogen and helium.
Astronomers search for oxygen using millimeter astronomy that can detect radio wavelengths emitted by molecules. Scientists also use spectroscopy to analyze the spectrum looking for wavelengths absorbed or admitted by specific molecules. While oxygen is the third most abundant element in the universe, astronomers historically find a surprising lack of oxygen molecules leaving scientists without a comprehensive picture of oxygen chemistry in the interstellar environment.
Astronomers have detected oxygen in the Orion nebula, but they believe oxygen in space is bound up with hydrogen in the form of water ice that clings to dust grains. The Orion nebula is a place where new stars are born, and they believe that it’s possible intense radiation from very hot young stars shocks the water ice in the sublimation splitting molecules and thereby releasing the oxygen. The new galaxy where the team has discovered molecular oxygen is called Markarian 231.
That galaxy is 561 million light-years away from Earth and is powered by a quasar. The galaxy also has an active supermassive black hole in the center, and its quasar is the closest quasar to Earth. Astronomers believe that Markarian 231 could have a pair of active supermassive black holes in the center spinning around each other at high speed. They believe that the active galactic nucleus is driving molecular outflow and producing continuous shocks that may release oxygen from water and molecular bonds. Molecular outflows in the galaxy are at high velocity according to the team.
This is the first time the team has detected molecular auction emissions in a galaxy outside of our own. The team says that the detected oxygen emission is located in regions that are about 32,615 light-years away from the center of the Markarian 231 galaxy. The team was also able to determine that the abundance of oxygen compared to hydrogen was about 100 times higher than what was previously discovered in the Orion nebula.