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| What looks like a faint dot in this James Webb Space Telescope image could be a groundbreaking discovery. Detailed data on galaxy GS-NDG-9422 from Webb’s NIRSpec shows that the light originates from the galaxy’s hot gas, which outshines its extremely hot stars (over 140,000 degrees Fahrenheit). This heating effect allows the gas to glow more brightly than the stars themselves. |
Using NASA’s James Webb Space Telescope to explore the early universe, astronomers have discovered a remarkable galaxy with an unusual light signature, suggesting that its gas outshines its stars. This galaxy, designated GS-NDG-9422, was formed around one billion years after the Big Bang and could represent a crucial transitional phase in galactic evolution, bridging the gap between the universe’s first stars and the more established galaxies we recognize today.
My first thought upon examining the galaxy’s spectrum was, ‘that’s weird,’ which is precisely what the Webb telescope was designed to uncover: new phenomena in the early universe that can enhance our understanding of cosmic history,stated lead researcher Alex Cameron from the University of Oxford. To further explore the unusual data, Cameron consulted with theorist Harley Katz.
Together, their team discovered that computer models simulating cosmic gas clouds heated by extremely hot, massive stars closely aligned with Webb’s observations. It appears these stars are significantly hotter and more massive than those in the local universe, which aligns with the distinct conditions of the early universe,” Katz noted, representing both Oxford and the University of Chicago.
In the local universe, typical hot, massive stars have temperatures between 70,000 and 90,000 degrees Fahrenheit (40,000 to 50,000 degrees Celsius). In contrast, the stars in galaxy 9422 exceed 140,000 degrees Fahrenheit (80,000 degrees Celsius). The research team believes that this galaxy is undergoing a brief but intense phase of star formation within a dense gas cloud, resulting in the creation of numerous massive, hot stars. The sheer number of photons emitted by these stars is causing the gas cloud to shine exceptionally brightly.
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| The comparison of data from the James Webb Space Telescope with a theoretical model reveals a striking similarity that caught the attention of lead researcher Alex Cameron, as detailed in a study published in Monthly Notices of the Royal Astronomical Society. The bottom graphic contrasts expected light from a typical galaxy, primarily from stars (white line), with a model showing light from hot nebular gas that outshines stars (yellow line), developed by Cameron’s collaborator Harley Katz. Their observations of galaxy GS-NDG-9422 show an unusual downturn in the spectrum, indicating a dominance of super-heated gas. While this is just one example, the team believes this finding could serve as a pivotal starting point for future research, as they seek more galaxies from around the one-billion-year mark in the universe’s history to uncover additional examples of this potential missing link in galactic evolution. |
In addition to its novelty, the phenomenon of nebular gas outshining stars is particularly intriguing because it aligns with predictions regarding the environments of the universe’s first generation of stars, known as Population III stars. “We know this galaxy doesn’t contain Population III stars, as Webb’s data reveals significant chemical complexity. However, the stars here are unlike those we typically encounter—these exotic stars could help us understand how galaxies evolved from primordial stars to the familiar types we recognize today,” noted Katz.
Currently, galaxy 9422 serves as a solitary example of this developmental phase, leaving many questions unanswered. Are these conditions typical for galaxies of this era, or are they an anomaly? What insights can they provide about even earlier phases of galaxy evolution? Cameron, Katz, and their colleagues are actively searching for additional galaxies to enhance this population, aiming to uncover the dynamics of the universe within the first billion years after the Big Bang.
“It’s an incredibly exciting time to utilize the Webb telescope to explore an epoch in the universe that was previously inaccessible,” Cameron remarked. We are only at the beginning of making new discoveries and deepening our understanding.The research paper is published in Monthly Notices of the Royal Astronomical Society.
The James Webb Space Telescope stands as the world’s premier space science observatory, solving mysteries within our solar system, examining distant worlds around other stars, and probing the intricate structures and origins of our universe. Webb is an international collaboration led by NASA, along with its partners, the ESA (European Space Agency) and CSA (Canadian Space Agency).