Key takeaways

  • Astronomers made the largest 3D map of 1 million distant galaxies hidden by the Magellanic Clouds.
  • These bright, irregular dwarf galaxies in the Southern Hemisphere block our view of many distant galaxies.
  • Using the VISTA telescope in Chile, scientists captured detailed images to see through gaps between stars.
  • The GASKAP survey helped correct for dust effects, revealing true colors and brightness of hidden galaxies.
  • Data from the Gaia satellite was used to distinguish between nearby stars and distant galaxies by tracking star movements.
A section of the Small Magellanic Cloud as seen by the VISTA telescope with distant galaxies circled in green. (Image credit: ESO/VISTA Magellanic Clouds Survey)

Astronomers have generated the greatest 3D depiction of 1 million distant galaxies, which would otherwise be covered by the Milky Way’s dwarf galaxy neighbors, the Magellanic Clouds.

The Magellanic Clouds are irregularly formed galaxies that are visible in the Southern Hemisphere sky. However, due to the brightness of these dwarf galaxies and their huge size in the night sky, the Milky Way’s companions obscure our view of many far more distant galaxies. As a result, when astronomers observe the universe’s billions of galaxies, they avoid this region of the sky.

“The Magellanic Clouds are beautiful galactic companions, but they, unfortunately, do block part of our view of objects further out,” Jessica Craig, a University of Keele astronomer and map-building team member, said in a statement. “Our work is helping overcome that, and in the process helping to fill in the gaps in our map of the universe.”

Craig and her colleagues addressed this issue by photographing the Magellanic Clouds in such high resolution that they could see through the gaps between the stars that comprise these galaxies. To create these photos, the scientists used the Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal Observatory in Chile.

The Small Magellanic Cloud obscures galaxies in the Southern Hemisphere. (Image credit: ESA/Hubble and Digitized Sky Survey 2)

However, these progressively distant “hidden” galaxies are especially difficult to view because material in the Magellanic Clouds makes them look fainter and redder than they are. To account for this impact, the scientists used a radio telescope called the Galactic Australian Square Kilometer Array Pathfinder Survey (GASKAP), which can see through the dust between Earth and other galaxies. The GASKAP data enabled scientists to generate a precise picture of gas and dust in the Magellanic Clouds, accounting for the degree of’reddening’ these components produce in the galaxies they conceal.

Because of the vast quantity of light sources in the Magellanic Cloud pictures, the human eye cannot discern between distant galaxies and nearby ones. However, because stars change positions whereas distant galaxies do not, the team was able to correctly label each light source using data from the star-mapping Gaia satellite.

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