Astronomers have created the largest 3D map of a million distant galaxies obscured by the Milky Way’s neighboring dwarf galaxies, the Magellanic Clouds.
The Magellanic Clouds form irregularly galaxies This is an amazing feature of the southern hemisphere sky, visible to the naked eye. But the brightness of these dwarf galaxies combined with the fact that they occupy a large area of the night sky means that Milky WayOur view of many distant galaxies is obscured by our neighbors. So when astronomers observe billions of galaxies universeThey tend to avoid this part of the sky.
“The Magellanic Clouds are beautiful galactic companions, but unfortunately they obscure some of our view of distant objects,” said Keele University astronomer and mapping team member Jessica Craig. a permit (Opens in a new tab). “Our work helps overcome this and, in the process, helps fill in the gaps in our map of the universe.”
Related: This gorgeous image from the Hubble Space Telescope shows turquoise waves rippling through the Milky Way’s companion
Craig and his colleagues tackled this problem by imaging the Magellanic Clouds at such high resolution that they were able to search for the gaps between the two images. stars that form these galaxies. To make these images, the team turned to the Visible and Infrared Scanning Telescope for Astronomy (VISTA) based at the Paranal Observatory in Chile.
But these increasingly distant “hidden” galaxies are harder to see because they appear dimmer and redder than they do due to the dust in the Magellanic Clouds. To explain this effect, the team turned to a radio telescope, the Australian Square Kilometer Survey Pathfinder Array (GASKAP), which can peer through the 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 “reddening” these factors cause in the galaxies that obscure them.
The Small Magellanic Cloud obscures the galaxies of the southern hemisphere. (Image credit: ESA/Hubble and Digitized Sky Survey 2)
Due to the large number of light sources in images of the Magellanic Cloud, the human eye alone cannot distinguish distant galaxies from nearby objects. But stars change position while distant galaxies stay in the same place, so the team was able to use the data to map the stars. Gaia Observatory Correctly classify each light source.
Astronomers have used a second technique to confirm the distinction between distant galaxies and relatively nearby stars. As the universe expands as more distant galaxies move away from Earth, the wavelength of light from those galaxies expands. The longest wavelengths of visible light are red, so astronomers describe this prolongation redshift.
The farther away an object is, the faster it recedes, so the redder its light appears, the more distant galaxies become redder than stars. By taking color into account, the team can remove the stars from their data even further.
Finally, the astronomers applied machine learning and artificial intelligence to sort galaxies and create a 3D map of an estimated one million galaxies.
Craig Present the results of the team In mid-July at the National Astronomy Meeting held at the University of Warwick in the United Kingdom
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