Astronomers first identified and mapped the distribution of water in distant galaxies when the universe was still in its infancy.
Water is an essential ingredient for the growth and development of life as we know it on Earth. Therefore, when looking for the possibility of another life outside the Earth or on other planets, the main criterion is the presence of water. And, of course, not only water. Water can be found as a solid or ice, and also as water vapor or gas. In search of life, we melt water in liquid form on the surface of the planet.
This time, astronomers are looking for the presence of water and its distribution within the galaxy. In particular, astronomers want to know the distribution of water and how it changes from ice or a solid to a gas, namely water vapour. This is important as a marker of areas experiencing increased energy to indicate where stars and black holes form.
In short, if there is moisture, then something important is happening in this area.
Astronomers at the Scuola Internazionale Superiore in Studi Avanzati, Italy, used the Atacama Large Millimeter/submmillimeter Array (ALMA) radio telescope to search for water in distant galaxies.
Galaxy J1135. This is the galaxy that was the target of ALMA observations. This galaxy is 12 billion light years away. This means that this galaxy was either quite young when it formed, or, from our observers’ point of view, it is an old galaxy that formed when the universe was still in its teens. At that time, the universe was only 1.8 billion years old.
As a result, these astronomers were able to map the distribution of water in this distant galaxy. This map is important for understanding the processes taking place in the J1135 galaxy, especially those related to the dynamics around the star-forming region, black holes, and the galaxy itself.
Water is one of the components that can reveal the history of physical processes in the galaxy. Water can be found as ice in molecular clouds. This is a dense region of gas and dust that becomes a trough for the birth of new stars in the galaxy.
Water in a molecular cloud
In a molecular cloud, water acts as a cloak or mantle covering the surface of interstellar dust grains. This interstellar dust is the main material for molecular clouds and the main catalyst for the formation of molecules in outer space. There are times when the calmness inside a cold molecular cloud is broken.
A collapse in a cloud that fuels star formation and releases heat, or a black hole that attracts matter and releases energy. Radiation from stars and other sources inevitably heats the water ice so that it sublimates into a gas, also known as water vapour. When water vapor is cooled, this gas will emit infrared light in the spectrum. It is from the emission of water vapor in the spectrum that astronomers can map the regions of energy formation in galaxies and gain new insights into the formation of galaxies.
Astronomers combine this information about the distribution of water with maps of other molecules, such as carbon monoxide, which are used to study the same phenomenon.
The formation of galaxies is also still a mystery. There are at least two theories of galaxy formation, namely the merger of small galaxies into large galaxies, or galaxies formed as a result of the formation of stars in immediate places.
Astronomers observe the J1135 galaxy using gravitational lensing techniques. This method allows astronomers to use a large object that is in the observer’s line of sight of the galaxy J1135. A high-mass object could be another galaxy or a cluster of galaxies. Light from the galaxy J1135 passing through a large mass object will be bent and amplified. In this way, astronomers can learn about the existence of these distant galaxies.