Newly Confirmed “Maisie’s Galaxy” is One of the Oldest Known Galaxies

Astronomers using the James Webb Space Telescope (JWST) have confirmed that a distant celestial object, known as “Maisie’s galaxy,” is one of the earliest galaxies in the universe. The object, named in honor of lead researcher Steven Finkelstein’s daughter, emitted light more than 13 billion years ago, placing it among the four oldest galaxies that have had their ages confirmed through spectroscopy.

“Maisie’s galaxy” was first detected during JWST’s debut season of observations in August 2022. Its extreme brightness and redshift, which indicates its distance and age, initially suggested its ancient origins. However, spectroscopy was required to confirm its actual age. Spectroscopy is a technique that splits light into component frequencies to reveal its brightness, heat, and chemical composition.

The study authors used the JWST’s Near Infrared Spectrograph to analyze the light of two ancient objects: Maisie’s galaxy and CEERS-93316, another galaxy discovered around the same time. Spectroscopic analysis confirmed the distant and ancient nature of Maisie’s galaxy, but the same was not true for CEERS-93316. The researchers found that intense light emissions from hot hydrogen and oxygen in CEERS-93316 made the galaxy appear bluer and thus older than it actually was. The revised estimate places CEERS-93316 at about 1 billion years after the Big Bang, removing it from the list of oldest known galaxies.

Maisie’s galaxy joins a short list of four other galaxies, also confirmed the JWST through spectroscopy, that formed within 300 million to 500 million years after the beginning of space-time. This discovery adds to our understanding of the early universe and highlights the importance of using spectroscopy to accurately determine the ages of galaxies.

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