Quantifying the amount of oxygen is key to understanding how matter cycles in and out of galaxies.
“This is by far the most distant galaxy for which the oxygen abundance has actually been measured. We’re looking back in time at this galaxy as it appeared 12 billion years ago,” said Alice Shapley, professor of astronomy and co-author of the study.
Knowing the abundance of oxygen in the galaxy called COSMOS-1908 is an important stepping stone toward allowing astronomers to better understand the population of faint, distant galaxies observed when the universe was only a few billion years old and galaxy evolution.
COSMOS-1908 contains approximately 1 billion stars.
In contrast, our Milky Way galaxy contains approximately 100 billion stars.
Furthermore, COSMOS-1908 contains approximately only 20 percent the abundance of oxygen that is observed in the Sun.
“Close galaxies are much brighter, and we have a very good method of determining the amount of oxygen in nearby galaxies,” said Ryan Sanders, astronomy graduate student and the study’s lead author in a paper published in the Astrophysical Journal Letters.
“Ryan’s discovery shows we can measure the oxygen and compare these observations with models of how galaxies form and what their history of star formation is,” Shapley noted.