The identification of a peculiar and unmatched galaxy from the early Universe may provide crucial insights into the beginnings of the cosmos, according to astronomers. Named GS-NDG-9422 (9422), this galaxy was discovered around one billion years post-Big Bang. It is remarkable for possessing a unique and unprecedented light signature, which suggests that its gas is outshining its stars. Researchers believe this “entirely new phenomenon” could represent a key transitional phase in the evolution of galaxies, bridging the gap between the Universe’s initial stars and the more familiar galaxies we recognize today.
The identification of a peculiar and unmatched galaxy from the early Universe may provide crucial insights into the beginnings of the cosmos, according to astronomers.
GS-NDG-9422 (9422) was discovered about one billion years after the Big Bang and is notable for its unique light signature, indicating that its gas outshines its stars.
This “entirely new phenomenon” is essential, researchers claim, as it may be a critical transitional phase in the evolution of galaxies that connects the Universe’s first stars with the more commonly recognized, established galaxies.
This extraordinary type of galaxy was observed by the $10 billion (£7.6 billion) James Webb Space Telescope (JWST), a collaboration between US, European, and Canadian space agencies, specifically designed to look back in time to the Universe’s infancy.
The findings were publicly shared today in a research article published in the Monthly Notices of the Royal Astronomical Society.
“Upon examining the galaxy’s spectrum, my initial thought was, ‘that’s odd,’ which is precisely what the Webb telescope was intended to uncover: completely new phenomena from the early Universe that will enhance our understanding of cosmic origins,” stated Dr. Alex Cameron, the lead researcher from the University of Oxford.
Cameron reached out to theorist Dr. Harley Katz to delve into the puzzling data. Collaboratively, their team discovered that computer simulations of cosmic gas clouds heated by incredibly hot, massive stars, to the degree that the gas outshines the stars, closely matched Webb’s findings.
“It seems these stars must be significantly hotter and larger than what we observe in our local Universe, which aligns with the fact that the early Universe had a vastly different environment,” noted Katz, who is affiliated with Oxford and the University of Chicago.
In the local Universe, typical hot, massive stars have temperatures ranging from 70,000 to 90,000 degrees Fahrenheit (40,000 to 50,000 degrees Celsius). The team estimates that the stars in galaxy 9422 exceed 140,000 degrees Fahrenheit (80,000 degrees Celsius).
The researchers believe the galaxy is currently undergoing a brief phase of intense star formation within a dense gas cloud, creating a plethora of massive, hot stars. The gas cloud is receiving such a high influx of light from these stars that it is glowing remarkably bright.
Beyond its uniqueness, the phenomenon of nebular gas outshining stars is noteworthy because it’s anticipated in the settings of the Universe’s first generation of stars, classified as Population III stars.
“While we know that this galaxy doesn’t contain Population III stars due to the Webb data showing too much chemical complexity, its stars differ from those we typically recognize—the distinct stars in this galaxy could offer insights into how galaxies evolved from primordial stars to the types we are familiar with,” explained Katz.
Currently, galaxy 9422 serves as a singular example of this phase in galaxy development, leaving many questions unanswered. Are such conditions common in galaxies from this era, or are they rare? What else might they reveal about even earlier stages of galactic evolution?
Cameron, Katz, and their research team are actively searching for additional galaxies to include in this category to gain a clearer understanding of the Universe’s conditions in the first billion years following the Big Bang.
“This is an incredibly exciting period, as we can utilize the Webb telescope to explore a time in the Universe that was previously unreachable,” said Cameron.
“We are only at the onset of fresh discoveries and deeper understanding.”
