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Galaxy GS-NDG-9422 Spectrum (NIRSpec)

Infographic titled Galaxy GS-NDG-9422, Nebular light outshines starlight. Graphic is divided horizontally with one spectrum on top, labeled Webb Data, and one on bottom, labeled Model Spectrum. A portion of both spectrums about an inch wide is highlighted with a vertical column labeled Slope Feature. There is a clear similarity between the top and bottom graphs, thought the top has more angular lines and the bottom is smoother and rounded.

This comparison of the data collected by the James Webb Space Telescope with a computer model prediction highlights the same sloping feature that first caught the eye of astronomer Alex Cameron, lead researcher of a new study published in Monthly Notices of the Royal Astronomical Society

The bottom graphic compares what astronomers would expect to see in a "typical" galaxy, with its light coming predominantly from stars (white line), with a theoretical model of light coming from hot nebular gas, outshining stars (yellow line). The model comes from Cameron’s collaborator, theoretical astronomer Harley Katz, and together they realized the similarities between the model and Cameron's Webb observations of galaxy GS-NDG-9422 (top). The unusual downturn of the galaxy's spectrum, leading to an exaggerated spike in neutral hydrogen, is nearly a perfect match to Katz’s model of a spectrum dominated by super-heated gas. 

While this is still only one example, Cameron, Katz, and their fellow researchers think the conclusion that galaxy GS-NDG-9422 is dominated by nebular light, rather than starlight, is their strongest jumping-off point for future investigation. They are looking for more galaxies around the same one-billion-year mark in the universe’s history, hoping to find more examples of a new type of galaxy, a missing link in the history of galactic evolution.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    03:32:36.89
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    -27:46:49.33
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Fornax

About the Data

  • Instrument
    InstrumentThe science instrument used to produce the data.
    NIRSpec
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    GS-NDG-9422
  • Object Description
    Object DescriptionThe type of astronomical object.
    Nebular dominated galaxy
  • Release Date
    September 25, 2024
  • Science Release
    In Odd Galaxy, NASA’s Webb Finds Potential Missing Link to First Stars
  • Credit
    Illustration: NASA, ESA, CSA, Leah Hustak (STScI)

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  • Half Res (For Display), 1920 × 1600
    png (521.81 KB)

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Details

Last Updated
Aug 28, 2025
Contact
Media

Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
laura.e.betz@nasa.gov

Illustration Credit

NASA, ESA, CSA, Leah Hustak (STScI)