Astronomers have created the largest-ever 3D map of a million distant galaxies obscured by the Milky Way’s neighboring dwarf galaxies, the Magellanic Clouds.
Magellanic clouds form irregularly galaxies It is a remarkable feature of the southern hemisphere sky, visible to the naked eye. But the brightness of these dwarf galaxies, along with the fact that they occupy a large part of the night sky, mean that Milky WayMany distant galaxies are obscured by our neighbors. So when astronomers look at billions of galaxies in UniverseThey tend to avoid this part of the sky.
“The Magellanic clouds are beautiful galactic companions, but unfortunately they block some of our view of distant objects,” said Jessica Craig, a Keele University astronomer and a member of the construction team. a permit (Opens in a new tab). “Our work helps overcome this and, in doing so, fill in the gaps in our map of the universe.”
Craig and his colleagues tackled this problem by imaging the Magellanic Clouds at such high resolution that they could search through the gaps between them. stars that make up these galaxies. To make these images, the team turned to the visible and infrared telescope astronomy (VISTA) is based at Paranal Observatory in Chile.
But these more distant “hidden” galaxies are especially hard to see because they appear fainter and redder than they are due to dust from the Magellanic Clouds. To explain this effect, the team turned to a radio telescope, the Australian Galactic Square Kilometer Survey Pathfinder (GASKAP), which can peer through dust between Earth and distant galaxies. The GASKAP data allowed scientists to create a detailed map of the gas and dust in the Magellanic Clouds and thus calculate how much “shyness” these factors cause the galaxies that obscure them.
Due to the large number of light sources in the images of the Magellanic Clouds, the human eye alone cannot distinguish between distant galaxies and nearby objects. But the stars change their positions while the distant galaxies stay in one place, so the team was able to use the star map data Gaia Observatory To properly classify each light source.
Astronomers have used a second technique to confirm the distinction between distant galaxies and relatively nearby stars. Since the universe expands when the farthest galaxies move away from Earth, the wavelength of light from these galaxies expands. The longer wavelengths of visible light are red, so astronomers call this elongation red shift.
The farther away an object is, the faster it moves away, and therefore the redder its light appears, so distant galaxies become redder than stars. By calculating the color, the team was able to remove stars from their data.
Finally, astronomers applied machine learning and artificial intelligence to order galaxies and create a 3D map of nearly a million galaxies.
Craig Present team results In mid-July at the National Astronomy Meeting held at the University of Warwick in the UK
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