2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Merging of two galaxies in a young universe as seen by the artist
Astronomers have seen the beginning of the merger of two very bright and massive galaxies that appeared a billion years after the Big Bang. The stars in them are born at an unusually high speed, which is not characteristic of most objects of that space age. The system of two rare galaxies, dubbed ADFS-27, was seen with the ALMA interferometer. This is reported in an article published in the Astrophysical Journal.
The galaxies ADFS-27 are located about 12.7 billion light-years from Earth in the direction of the constellation Dorado. For the first time, astronomers saw the system in images from the Herschel Space Telescope. Observations have shown that an object that initially appeared to be one red dot in the images may in fact be two very distant objects. Subsequent observations with the Atacama Pathfinder Experiment telescope confirmed this hypothesis and helped collect the necessary data to further study the system with ALMA.
The new images show that the ADFS-27 system consists of two ultra-bright infrared galaxies in which active star formation processes are taking place. The objects contain about 50 times more clouds of molecular gas than the Milky Way - about 2.5 × 1011 solar masses. This is enough to produce 2, 4 thousand Suns over a hundred million years. Once upon a time in galaxies, there was already a burst of star formation due to the fact that they passed close to each other. “Most of the gas will soon turn into stars. Current observations show that these two galaxies are indeed producing stars at a frantic rate, about a thousand times faster than our own galaxy,”comments Dominik Riechers, main author of the article.
Composite image of a pair of ADFS-27 galaxies
Objects, between which are 30 thousand light years, move at a speed of several hundred kilometers per second relative to each other. In the future, they are likely to merge into one massive elliptical galaxy - according to scientists, it will take hundreds of millions of years. Perhaps this object will even become the nucleus of an entire cluster of galaxies in the future.
Thanks to the ALMA telescope, astronomers are able to obtain detailed images of distant objects. For example, scientists filmed the surface of the distant red giant W Hydra and the star Betelgeuse in high resolution, the atmosphere of the red supergiant Antares and dust rings near Proxima Centauri.
One of the oldest galaxies known today is UDFj-39546284, composed of blue stars that existed 13.4 billion years ago, about 380 million years after the Big Bang. The oldest spiral galaxy known to date is A1689B11. It was formed 2, 6 billion years after the Big Bang.