Galactic Pioneer MXDFz4.4 (Unannotated Hubble and Webb Image)

stsci_2026-014c June 23rd, 2026

Credit: Image: NASA, ESA, STScI, Ilias Goovaerts, Marc Rafelski, Anton Koekemoer (STScI); Image Processing: Alyssa Pagan (STScI)

Oddball galaxy MXDFz4.4 existed only 1.4 billion years after the big bang, when the universe was still a ?swirl? of opaque and clear gas as the Era of Reionization was ending.

Detailed visible-light images from NASA?s Hubble Space Telescope revealed that several bursts of younger stars cleared the space in and around the galaxy. The team sifted through extensive Hubble observations that produced deep exposures of the field where this galaxy is located.

The color assignments in the image emphasize the specific wavelengths of light Hubble observed where ionizing photons from MXDFz4.4 were detected, which transformed the gas around them from opaque to clear.

Researchers have long sought evidence to explain how the universe transitioned from foggy to transparent ? and Hubble has provided the first example this close to the Era of Reionization of how that might have happened within an individual galaxy. ?Hubble returned the only view that shows the galaxy?s ionizing photons ? light capable of clearing the ?fog? in and around the galaxy,? said lead author Ilias Goovaerts, a postdoctoral fellow at the Space Telescope Science Institute in Baltimore.

Provider: Space Telescope Science Institute

Image Source: /image/stsci/2026-014c

Curator: STScI

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