This "baby galaxy," named RXCJ0600-z6, was spotted by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, which uses gravitational lensing to find galaxies formed in the early days of the universe.
The galaxy in question was estimated to have a mass of 2-3 million solar masses, meaning 2-3 million times more mass than the Sun. However, this is just 1/100th the size of the Milky Way, which is around 1.5 trillion solar masses.
The size is an important factor, as it is precisely because of their small sizes that many galaxies in the early days of the universe remain undetected by scientists. The light coming from them - light and size are linked - simply wasn't bright enough for telescopes on Earth to actually visualize them.
However, because ALMA uses gravitational lensing the brightness from RXCJ0600-z6 was highly magnified. This made it "an ideal target for studying the properties and structure of typical baby galaxies," University of Cambridge Kavli Senior Fellow Nicolas Laport said in a statement.
Gravitational lensing is a natural phenomenon in which the gravity of a massive body, such as a galaxy or a galaxy cluster, bends the light that is being emitted from a distant object. This allows the gravity of the massive object to act like a lens, and through this method the light of the distant object is intensified and its shape is enlarged.
ALMA observed RXCJ0600-z6 as it was when the universe itself was around 900 million years old – a mere 7% of its current age. Upon further analysis of the data, it was determined that a part of this source is seen 160 times brighter than it is in reality.
Finding galaxies such as this one is crucial and could impact some of our most fundamental knowledge of the universe. Galaxies formed in the early days of the universe are much smaller and therefore faint and difficult to detect. The more knowledge and data we can accumulate on these early galaxies the better, as it will allow us to gain a complete picture of how they form and evolve over time as the universe expands.
Proof of the importance of such studies can be seen in the discovery of RXCJ0600-z6, as upon observing it astronomers found that the galaxy was rotating. Prior to this discovery it was believed that the gas in young galaxies has random and chaotic movement patterns, but this galaxy, and several others discovered by ALMA, have challenged this theory. Of the galaxies which have contributed to this new research, RXCJ0600-z6 is the smallest one.
The discovery of RXCJ0600-z6 also looks promising when it comes to the future of our study of the universe, according to DAWN fellow at the Niels Bohr Institute, Seiji Fujimoto. Due to the high magnification factor of the galaxy it will be possible to observe it through the James Webb Space Telescope (JWST) in the coming months. The combination of ALMA and JWST will allow astronomers to further understand the intricate properties of gas and stars, and all of their internal motions inside of the small galaxy. There is hope that in the future our technology will advance to such a degree that even individual stars will be able to be viewed using gravitational lensing.
Dr. Adi Zitrin of the physics department at Ben-Gurion University shares Fujimoto's optimism about our future understanding of the universe, saying that "it is great to see the range of science enabled by gravitational lensing in recent years. Lensing, paired with new and advanced instruments that are being built, such as the James Webb Space Telescope (JWST), will surely lead to more exciting and unprecedented discoveries."