(ORDO NEWS) — There are hundreds of billions of galaxies in the universe, each containing billions of stars and located in different corners of the sky.
But in some directions, nearby galaxies obscure the view of more distant space. Now a team from Keele University has created the largest ever map of previously hidden galaxies.
Astronomers looked at the Magellanic Clouds, a pair of galaxies visible from the southern hemisphere that are so close to us that they can be seen with the naked eye.
These two galaxies occupy a large area of the sky, blocking the view of the galaxies further away. Because of this, astronomers looking for distant galaxies usually avoid this part of the sky.
Using the VISTA Survey Telescope in Chile, the team photographed two nearby galaxies at a resolution high enough to see the gaps between the stars in each.
Thus, they were able to see the most distant galaxies, which appear dimmer and redder than they really are due to the dust that is still in front of them.
The solution to the problem is to use a radio telescope, and in this case the GASKAP Galactic Australian Square Kilometer Array provides a detailed map of the gas in the Magellanic Clouds, allowing measurements of the dust content and thus the degree of reddening of the stars.
Another task is to distinguish stars from galaxies, and there are so many of them that it is impossible to do it manually.
So Keel’s team used data from the Gaia observatory to measure tiny shifts in the positions of stars over time, while far more distant galaxies stayed in the same place.
Galaxies are also redder than brighter stars, so the color helped remove more stars from the dataset.
The color also shows how far away the galaxies are (through their redshift resulting from the expansion of the universe).
Machine learning, when the software uses artificial intelligence tools, performs the final sorting of the remaining data.
The result of all this work was the largest ever 3D map of galaxies previously hidden behind the Magellanic Clouds, covering about 1 million galaxies.
Jessica Craig comments: “Magellan clouds are great galactic companions, but unfortunately they obscure part of our view of objects farther away. Our work helps overcome this challenge and in the process helps fill in the gaps in our map of the universe.”
Contact us: [email protected]