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ScienceJune 18, 2026

Hubble Glimpses Merging Galaxy Clusters

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NASA
1d ago

This NASAHubble Space Telescopeimage features a galaxy cluster, called CL0016+1609 or MACS J0018.5+1626, that is very bright at X-ray wavelengths and is one of the most extensively studied clusters at X-ray and radio wavelengths.

TheX-ray observationsof this cluster revealed that it is two clusters merging along our line of sight.

Researchers requested time to observe CL0016+1609 with Hubble’sAdvanced Camera for Surveysbecause that data would help them accurately measure the cluster’s dark-matter distribution, which helps them study the merger and the role of CL0016+1609 in the large-scale structure of the universe.

Hubble can’t directly see dark matter, but its infrared and visible light observations can detect dark matter’s gravitational lensing effects on the normal matter Hubble observes.

The data in this image also includes observations with Hubble’sWide Field Camera 3taken as part of an observing program that obtained the first Hubble infrared images of 46 massive galaxy clusters and looked for distant galaxies gravitationally lensed by these clusters.

Called RELICS, this survey found some 300 high-redshift candidate galaxies lensed by these clusters.

You can see the faint vertical arc of one of these distant galaxies in the image above.

Look for it just to the left of the large elliptical galaxies in the center of the image.

Another brighter, though shorter arc is visible just above and to the right of the large elliptical galaxies in the center of the image.

Claire AndreoliNASA’sGoddard Space Flight Center, Greenbelt, MDclaire.andreoli@nasa.gov

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