Looking into the early universe through NASA’s James Webb Space Telescope, astronomers have made a groundbreaking discovery: a galaxy exhibiting an unusual light signature believed to stem from its gas being more luminous than its stars. This galaxy, dubbed GS-NDG-9422 (9422), was identified around one billion years after the big bang and might represent a crucial transitional phase in the development of galaxies, situated between the universe’s first stars and the established galaxies we recognize today.
“When I first observed the galaxy’s spectrum, my immediate reaction was ‘that’s strange,’ perfectly aligning with the Webb telescope’s purpose of uncovering entirely new phenomena from the early universe, which will enhance our understanding of cosmic evolution,” remarked lead researcher Alex Cameron from the University of Oxford.
Cameron consulted with theorist Harley Katz to delve into the peculiar findings. Together, their team discovered that simulations of cosmic gas clouds heated by exceptionally hot, massive stars— to the point where the gas was more luminous than the stars themselves— aligned closely with the observations made by Webb.
“It appears that these stars are significantly hotter and more massive than those we observe in our local universe, which is logical given that the early universe had a distinctly different environment,” explained Katz, affiliated with both Oxford and the University of Chicago.
In our local universe, typical hot stars register temperatures between 70,000 and 90,000 degrees Fahrenheit (40,000 to 50,000 degrees Celsius), whereas the stars in galaxy 9422 exceed 140,000 degrees Fahrenheit (80,000 degrees Celsius).
The research team speculates that this galaxy is currently experiencing a brief phase of vigorous star formation within a dense gas cloud, resulting in the creation of numerous massive, hot stars. The intense light emitted is causing the gas cloud to shine with extraordinary brilliance.
Beyond its uniqueness, the phenomenon of gas outshining stars is particularly interesting because it was anticipated in the environments surrounding the universe’s initial generation of stars, known as Population III stars.
“Though we can ascertain that this galaxy lacks Population III stars, as the Webb data indicates excessive chemical complexity, its stars differ significantly from what we typically observe. The unique characteristics of the stars in this galaxy might provide insight into how galaxies evolved from primordial stars to the ones we recognize today,” Katz noted.
At this stage, galaxy 9422 serves as a solitary example of this phase in galactic development, leaving numerous questions unaddressed. Are these conditions prevalent among galaxies formed during this era, or are they rare? What insights might they offer about the earlier stages of galaxy evolution? Cameron, Katz, and their team are actively seeking additional galaxies to enrich this population and deepen our understanding of the universe’s status within the first billion years following the big bang.
“It’s an exhilarating time as we utilize the Webb telescope to investigate aspects of the universe that were previously unattainable,” stated Cameron. “We are merely scratching the surface of new discoveries and insights.”
The findings are documented in the Monthly Notices of the Royal Astronomical Society.
