Astronomers are building a three-dimensional map of millions of distant galaxies that are normally blocked from view by the Magellanic Clouds, a pair of galaxies that orbit the Milky Way. The map will be the largest yet of such hidden galaxies and may lead to new insights about how stars and galaxies evolve.
at Keele University in the UK and her colleagues are using data from two different telescopes and one space observatory to make the map.
The researchers started by looking at near-infrared images of the Magellanic Clouds taken by the Visible and Infrared Survey Telescope for Astronomy (VISTA) in Chile. These images are detailed enough to show distant galaxies peeking through gaps between the stars in the Magellanic Clouds. However, light from the galaxies has to travel through the dust that fills the Magellanic Clouds, which acts like a filter to make the galaxies appear artificially faint and red in images.
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Researchers must correct these effects to determine where a galaxy is in space, says Craig. To do so, the researchers used observations of the dust made by the GASKAP-HI telescope in Australia. They cross-referenced that data with what they knew about galaxies behind the dust.
Finally, they compared the colour-corrected images with observations from the Gaia space observatory to ensure that they weren鈥檛 confusing light emanating from galaxies with the glow of closer stars. They used a machine learning algorithm for this task because there were millions of stars and galaxies to be untangled.
So far, Craig and her team have completed the mapping process for the smaller of the Magellanic Clouds and expect the whole map to be completed within the next year. She presented the work at the in Coventry, UK, on 14 July.
at the National Science Foundation鈥檚 NOIRLab in Arizona says that understanding galaxies close to the Magellanic Clouds could further our understanding of how galaxies evolve in general. Some of those nearby galaxies may have originated when the two Magellanic Clouds interacted in the past. The details of this interaction, possibly a collision, aren鈥檛 fully understood. Olsen says that it may even be possible to learn more about whether there is a massive black hole within the Large Magellanic Cloud based on the new map.
After Craig and the team complete their map of millions of previously obscured galaxies, they want to apply the same mapping method to the Milky Way to see what may be hiding in the dusty regions of our own galaxy.
