Galaxy MXDFz4.4 (Hubble and Webb Image)

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, which combines data from the Hubble and James Webb space telescopes, 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.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, which combines data from the Hubble and James Webb space telescopes, 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.This image was created from Hubble data from the following proposals: 9978 (HUDF; S. V. W. Beckwith et al. 2006), 9425 (GOODS; M. Giavalisco et al. 2004), 12060, 12061, 12062 (CANDELS; S. Faber, A. Grogin et al. 2011, A. M. Koekemoer et al. 2011), 12177, 12328 (3D-HST; P. Van Dokkum, G. B. Brammer et al. 2012), 15647 (UVCANDELS; H.Teplitz, X. Wang et al. 2025), 12534 (H. I. Teplitz et al. 2013), 13872 (HDUV; P. A. Oesch et al. 2018) and JWST data from the following proposal: 1180 (JADES; D. J. Eisenstein et al. 2023)

Image Description: Thousands of galaxies appear across the black background of space. The galaxies range in size, from big blobs and larger face-on spirals to short lines and tiny dots. The galaxies appear in a variety of colors, including orange, white, pink, and blue. One prominent foreground star appears toward the lower right with several diffraction spikes. A white square highlights one tiny pinpoint of blue light in the top third, which is blown up in a box above it and labeled MXDFz4.4. The galaxy has a light blue core with some yellow and red blotches around its edges.