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 This is an amazing feature of the sky of the southern hemisphere, visible with 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 in UniverseThey tend to avoid this part of the sky.
“The Magellanic Clouds are beautiful galactic companions, but, unfortunately, they obscure part of our view of distant objects,” said Keele University astronomer and map-building team member Jessica Craig. a permit (Opens in a new tab). “Our work helps overcome that, and in the process we help fill in the gaps in our map of the universe.”
Craig and her colleagues tackled this problem by imaging the Magellanic Clouds at such high resolution that they could search the gaps between the two images. stars that make up these galaxies. To make these images, the team turned to the visible and infrared scanning telescope for astronomy (VISTA) is based at Paranal Observatory in Chile.
But these increasingly distant “hidden” galaxies are harder to see because they appear fainter and redder than they are due to 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 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 to the galaxies obscuring them.
Due to the huge number of light sources in the Magellanic Cloud images, the human eye alone cannot distinguish distant galaxies from nearby objects. But the 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 To properly 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 farther away galaxies move away from Earth, the wavelength of light from these galaxies expands. The longer 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 the stars. By taking color into account, the team can remove stars from their data further.
Finally, astronomers applied machine learning and artificial intelligence to order galaxies and create a 3D map of an estimated one million galaxies.
Craig Present team results In mid-July at the National Astronomy Meeting held at the University of Warwick in the UK