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Galaxy MXDFz4.4 (Hubble and Webb Image)

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.

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.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    03:32:39.64
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    -27:47:16.30
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Fornax
  • Distance
    DistanceThe physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
    12.4 billion light-years away to MXDFz4.4
  • Dimensions
    DimensionsThe physical size of the object or the apparent angle it subtends on the sky.
    This image is about 1.6 arcminutes across.

About the Data

  • Data Description
    Data DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
    Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.

    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)

  • Instrument
    InstrumentThe science instrument used to produce the data.
    Hubble> ACS/WFC Webb> NIRCam
  • Filters
    FiltersThe camera filters that were used in the science observations.
    Hubble> F435W, F606W, F775W, F814W, F850L, Webb> F090W, F115W, F150W, F182M, F200W, F210M, F277W, F335M, F356W, F410M, 430M, F444W
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    MXDFz4.4
  • Object Description
    Object DescriptionThe type of astronomical object.
    Ionizing galaxy
  • Release Date
    June 23, 2026
  • Science Release
    Hubble Details Early Galaxy Transforming Neighborhood
    Read the release
  • Credit
    Image: NASA, ESA, CSA, STScI, Ilias Goovaerts (STScI), Marc Rafelski (STScI, JHU), Anton Koekemoer (STScI); Image Processing: Alyssa Pagan (STScI)

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  • 2000 × 2000
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  • Unannotated Full Res (For Print), 3200 × 3200
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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.
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

These images were acquired by the ACS/WFC instrument on Hubble and the NIRCam instrument on Webb. Several filters were used to sample varying wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue (HST)= F435W, Green (HST)= F606W + F775W + F814W + F850L, Red (Webb)= F090W + F115W + F150W + F182M + F200W + F210M + F277W + F335M + F356W + F410M + 430M + F444W

Compass and Scale
Compass and ScaleAn astronomical image with a scale that shows how large an object is on the sky, a compass that shows how the object is oriented on the sky, and the filters with which the image was made.

Related Images & Videos

Illustration shows a closeup of a galaxy forming in the early universe. It appears chaotic and takes up most of the frame, from bottom left to top right. At the center are several bright white and blue blobs, which are areas of concentrated star formation. The blue becomes slightly darker in areas around this, taking up more than half of the galaxyu2019s overall size. There are smaller regions of bright blue star formation throughout this section. The galaxyu2019s edges, also irregularly shaped, are a medium blue, and smaller areas of star formation are apparent. The black background of space surrounds the galaxy.

Galaxy MXDFz4.4 (Artist's Concept)

This illustration portrays galaxy MXDFz4.4 when it existed 1.4 billion years after the big bang. At this time, the universe was still a mix of opaque and transparent gas as the Era of Reionization was gradually ending.

Image with compass arrows and color key. Thousands of galaxies appear across the black background of space in a range of sizes and colors. A white square highlights one pinpoint of blue light in the top third, which is blown up in a box above it and labeled MXDFz4.4. To the top left is a color key showing which HST ACS/WFC and JWST NIRCam filters were used to create the image and which visible-light color was assigned to each. Hubble: F435W (blue), F606W, F775W, F814W, F850LP (green); JWST: F090W, F115W, F150W, F182M, F200W, F210M, F277W, F335M, F356W, F410M, F430M, F444W (red). At the bottom left is a scale bar labeled 30 arcseconds. The length of the scale bar is about one fourth of the image. At the bottom right are compass arrows indicating the orientation of the image on the sky. The east arrow points toward 9 ou2019clock. The north arrow points toward 120 ou2019clock.

Galaxy MXDFz4.4 (Hubble and Webb Compass Image)

This shows the galaxy MXDFz4.4, enlarged at right, in the Hubble Ultra Deep Field (HUDF), captured by both the Hubble Space Telescope’s Advanced Camera for Surveys (ACS) and the James Webb Space Telescope’s NIRCam (Near-Infrared Camera).

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Details

Last Updated
Jun 23, 2026
Location
NASA Goddard Space Flight Center
Contact
Media

Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov

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