It was an international team of astronomers who detected the oldest oxygen emission in the Universe, thanks to the observation of a distant galaxy with abundant concentrations of cosmic dust, this Wednesday revealed the European Observatory of the South (OES).
This cosmic dust (nothing more than small particles of matter, formed from the death of generations of older stars) that is at bottom the basis for the constitution of new stars, planets and complex molecules, including those that give rise life. Nowadays, it is abundant, but interstellar dust was, however, scarce in the early days of the Universe, before the first generations of stars began to die.
This team of astronomers, led by Nicolas Laporte of University College London in the United Kingdom, used the world’s largest radio telescope, the ALMA, and was able to observe the emission of oxygen ionized by the galaxy “A2744_YD4”. For researchers, this is the most distant, and therefore oldest, detection of oxygen in the Universe, according to an OES statement.
The “A2744_YD4” is the farthest and youngest galaxy ever captured by the ALMA. That was when the Universe was about 600 million years old, and the first stars and galaxies were forming. According to the group of astronomers, the detection of a lot of interstellar dust in the “A2744_YD4” indicates that older dwarf supernovae “must have contaminated this galaxy”. For scientists, the observation of cosmic dust in the early universe, provides new information about the precise moment when the first stellar explosions, hot and bright stars, took the Universe out of the darkness.
This time determination of the “cosmic aurora” is seen as a treasure for modern astronomy and can be sought indirectly through the study of the oldest (mostly composed of silicon, carbon and aluminum) interstellar dust. The “A2744_YD4” observations with the ALMA were only possible because the galaxy is behind the cluster of galaxies “Abell 2744”, which acted as a kind of “giant telescope”, enlarging the “A2744_YD4”, a phenomenon called Gravitational lens (formed due to a distortion in space-time, caused by a massive body between a star and an observer).
Astronomers are now able to estimate that the galaxy “A2744_YD4” has a cosmic dust equivalent to six billion solar masses and a stellar mass of two billion solar masses. This group of scientists has discovered that stars are forming in the galaxy at an average of 20 solar masses per year (in the Milky Way, the mean is one solar mass per year), which may explain why cosmic dust formed So quickly on “A2744_YD4”.